Source: The Conversation – Canada – By Richa Shivakoti, Research Lead, Migration Governance at the Canada Excellence Research Chair in Migration & Integration program, Toronto Metropolitan University
The MaRS urban innovation hub building in Toronto. Canada may benefit from the American H-1B visa fee increase by attracting highly skilled tech workers and others from abroad to Canada instead of the United States.(WikiMedia), CC BY
The United States government recently announced a US$100,000 H-1B visa fee on new applications, which will affect highly educated workers from abroad who are seeking jobs in the U.S. This policy could have ripple effects for Canada by reducing the emigration of Canadians going to work in the U.S. — and by attracting a talented workforce to the country.
The H-1B visa program was created in 1990 for applicants with at least a bachelor’s degree or higher to work in the U.S. The current annual statutory cap is 65,000 visas, with 20,000 additional visas for professionals from abroad who graduate with a master’s or doctorate from an American institution of higher learning.
Instead, this massive increase in fees will make it much more expensive for firms to hire highly educated and skilled immigrants.
The impact on Canadians
Approximately 828,000 Canadian-born immigrants lived in the U.S. as of 2023, many of whom moved to the country via employment channels. Canadians made up one per cent of the total H-1B applications in 2019, and the new H-1B visa fee could reduce the number of Canadians moving to the U.S. for work.
This is especially true in the tech sector, as noted by Prime Minister Mark Carney in his recent remarks at the Council of Foreign Relations in New York:
“We are a leading developer of AI. And our research universities are some of the biggest producers in volume of AI, computing and quantum talent in the world. Unfortunately, most of them go to the United States. I understand you’re changing your visa policy, I hear, so going to hang onto a few of those.”
But another possibility is that American businesses could shift towards using the TN visa — an American non-immigrant visa for citizens of Canada and Mexico to work in specific professional-level jobs — to hire more Canadian workers. Canadians are eligible for the work permit under the Canada-US-Mexico-trade agreement.
These companies could then bypass paying the new H-1B visa fee while still hiring Canadian talent.
Prime Minister Mark Carney’s full remarks to the Council of Foreign relations. (Reuters)
Competition for global talent
Various countries, including Canada, are competing to attract and retain global talent. For many highly educated people from abroad seeking work in the U.S., especially recent international graduates of American universities, the new visa fee might result in fewer employment opportunities. As they start to look elsewhere, Canada could be an attractive destination if immigration pathways can be provided in a timely fashion.
So Canada should be proactive in working with these companies as they plan alternate pathways to retain their workforce.
This sudden and drastic change in the H-1B visa fee by the Donald Trump government presents a window of opportunity for Canadian policymakers to react quickly and offer pathways to recruit such foreign talent. The Canadian government seems to be paying attention. Carney told a recent news conference in London:
“Not as many of those people are going to get visas to the United States. And these are people with lots of skills that are enterprising, and they’re willing to move to work …. So it’s an opportunity for Canada, and we’re going to take that into account. And we’ll have a clear offering on that.”
In the current environment, policy officials inside and outside of government can provide ideas on creating targeted policies and pathways to recruit talented workers to Canada.
Richa Shivakoti receives funding from the Social Science and Humanities Research Council.
Anna Triandafyllidou receives funding for research related to high-skilled migration and its governance from the Tri-Council Agency and the Social Sciences and Humanities Research Council of Canada, as well as Horizon Europe (Link4Skills research project).
Source: The Conversation – USA – By Donald Nieman, Professor of History and Provost Emeritus, Binghamton University, State University of New York
Supporters of free speech gather in September 2025 to protest the suspension of ‘Jimmy Kimmel Live!’, across the street from the theater where the show is produced in Hollywood.Mario Tama/Getty Images
Bipartisan agreement is rare in these politically polarized days.
But that’s just what happened in response to ABC’s suspension of “Jimmy Kimmel Live!” The suspension followed the Federal Communications Commission chairman’s threat to punish the network for Kimmel’s comments about Charlie Kirk’s alleged killer.
While bipartisan agreement may be rare, it’s not surprising that it came in defense of the First Amendment – and a popular TV show. A recent poll found that a whopping 90% of respondents called the First Amendment “vital,” while 64% believed it’s so close to perfection that they wouldn’t change a word.
In just 45 words, it bars Congress from establishing or preventing the free exercise of religion, interfering with the peoples’ right to assemble and petition, or abridging freedom of speech or the press.
Handwritten revisions by senators during the process of altering and consolidating the amendments to the U.S. Constitution proposed by James Madison of Virginia. National Archives
Soured on bills of rights
Building a strong national government was the focus of Madison and the other delegates who met in Philadelphia in May 1787 to draft the Constitution.
The government could not pay its debts, defend the frontier or protect commerce from interference by states and foreign governments.
Although Madison and the other framers aimed to create a stronger national government, they cared about protecting liberty. Many had helped create state constitutions that included pioneering bills of rights.
By the time the Constitutional Convention met, however, Madison had soured on such measures. During the 1780s, he had watched with alarm as state legislatures trampled on rights explicitly guaranteed by their constitutions. Bills of rights, he concluded, weren’t sufficient to protect rights.
The Constitution they wrote created a government powerful enough to promote the national interests while maintaining a check on state legislatures. It also established a system of checks and balances that ensured federal power wasn’t abused.
In the convention’s waning days, delegates briefly discussed adding a bill of rights but unanimously decided against it. They had sweated through almost four months of a sweltering Philadelphia summer and were ready to go home. When Virginia’s John Rutledge noted “the extreme anxiety of many members of the Convention to bring the business to an end,” he was stating the obvious. With the Constitution in final form, few had the appetite to haggle over the provisions of a bill of rights.
That decision nearly proved fatal when the Constitution went to the states for ratification.
The new Constitution’s supporters, known as Federalists, faced fierce opposition from Anti-Federalists who charged that a powerful national government, unrestrained by a bill of rights, would inevitably lead to tyranny.
Ratification conventions in three of the most critical states – Massachusetts, New York and Virginia – were narrowly divided; ratification hung in the balance. Federalists resisted demands to make ratification contingent on amendments suggested by state conventions. But they agreed to add a bill of rights – after the Constitution was ratified and took effect.
The three critical states ratified without condition, and by midsummer 1788, the Constitution had been approved.
However, when the First Congress met in March 1789, the Federalist majority didn’t prioritize a bill of rights. They had won and were ready to move on.
Madison, now a Federalist leader in the House of Representatives, insisted that his party keep its word. He warned that failure to do so would undermine trust in the new government and give Anti-Federalists ammunition to demand a new convention to do what Congress had left undone.
But Madison wasn’t just arguing for his party keeping its word. He had also changed his mind.
The ratification debates and Madison’s correspondence with Thomas Jefferson led him to think differently about a bill of rights. He now thought it harmless and possibly helpful. Its provisions, Madison conceded, might become “fundamental maxims of a free government” and part of “the national sentiment.” Broad popular support for a bill of rights might provide a check on government officials and how they wielded power.
Madison pushed his colleagues relentlessly. Wary of provisions that would weaken the national government, he developed a slate of amendments focused on individual rights. Ultimately, Congress approved 12 amendments – ensuring rights from freedom of speech to protection from cruel and unusual punishment – and sent them to the states for ratification.
As Madison anticipated, the First Amendment wasn’t a cure for a government bent on suppressing dissent. From the Sedition Act in the 1790s to McCarthyism in the 1950s and the Trump administration’s assault on the First Amendment, government has used its awesome powers to pursue and punish critics.
Perhaps the ultimate protection for First Amendment rights is “national sentiment,” as Madison suggested. Norm-breaking presidents can disregard the law, and judges may cave. But public sentiment is a powerful force, as Jimmy Kimmel can attest.
Donald Nieman receives funding from the National Endowment for the Humanities and the American Council of Learned Societies. He is affiliated with Braver Angels.
In a series of cases over the past 15 years, the Supreme Court has moved in a pro-presidential direction.Geoff Livingston/Getty Images
President Donald Trump set the tone for his second term by issuing 26 executive orders, four proclamations and 12 memorandums on his first day back in office. The barrage of unilateral presidential actions has not yet let up.
These have included Trump’s efforts to remove thousands of government workers and fire several prominent officials, such as members of the Corporation for Public Broadcasting and the chair of the Commission on Civil Rights. He has also attempted to shut down entire agencies, such as the Department of Education and the U.S. Agency for International Development.
As a political science scholar who studies presidential power, I believe Trump’s recent actions mark the culmination of the unitary executive theory, which is perhaps the most contentious and consequential constitutional theory of the past several decades.
A prescription for a potent presidency
In 2017, Trump complained that the scope of his power as president was limited: “You know, the saddest thing is that because I’m the president of the United States, I am not supposed to be involved with the Justice Department. I am not supposed to be involved with the FBI, I’m not supposed to be doing the kind of things that I would love to be doing. And I’m very frustrated by it.”
The unitary executive theory suggests that such limits wrongly curtail the powers of the chief executive.
Formed by conservative legal theorists in the 1980s to help President Ronald Reagan roll back liberal policies, the unitary executive theory promises to radically expand presidential power.
There is no widely agreed upon definition of the theory. And even its proponents disagree about what it says and what it might justify. But in its most basic version, the unitary executive theory claims that whatever the federal government does that is executive in nature – from implementing and enforcing laws to managing most of what the federal government does – the president alone should personally control it.
This means the president should have total control over the entire executive branch, with its dozens of major governmental institutions and millions of employees. Put simply, the theory says the president should be able to issue orders to subordinates and to fire them at will.
President Donald Trump signs executive orders in the Oval Office next to a poster displaying the Trump Gold Card on Sept. 19, 2025. AP Photo/Alex Brandon
The president could boss around the FBI or order the U.S. attorney general to investigate his political opponents, as Trump has done. The president could issue signing statements – a written pronouncement – that reinterpret or ignore parts of the laws, like George W. Bush did in 2006 to circumvent a ban on torture. The president could control independent agencies such as the Securities and Exchange Commission and the Consumer Product Safety Commission. The president might be able to force the Federal Reserve to change interest rates, as Trump has suggested. And the president might possess inherent power to wage war as he sees fit without a formal authorization from Congress, as officials argued during Bush’s presidency.
A constitutionally questionable doctrine
A theory is one thing. But if it gains the official endorsement of the Supreme Court, it can become governing orthodoxy. It appears to many observers and scholars that Trump’s actions have intentionally invited court cases by which he hopes the judiciary will embrace the theory and thus permit him to do even more. And the current Supreme Court appears ready to grant that wish.
Until recently, the judiciary tended to indirectly address the claims that now appear more formally as the unitary executive theory.
During the country’s first two centuries, courts touched on aspects of the theory in cases such as Kendall v. U.S. in 1838, which limited presidential control of the postmaster general, and Myers v. U.S. in 1926, which held that the president could remove a postmaster in Oregon.
In 1935, in Humphrey’s Executor v. U.S., the high court unanimously held that Congress could limit the president’s ability to fire a commissioner of the Federal Trade Commission. And in Morrison v. Olson the court in 1988 upheld the ability of Congress to limit the president’s ability to fire an independent counsel.
Some of those decisions aligned with some unitary executive claims, but others directly repudiated them.
These decisions clearly suggest that long-standing, anti-unitarian landmark decisions such as Humphrey’s are on increasingly thin ice. In fact, in Justice Clarence Thomas’ 2019 concurring opinion in Seila Law LLC v. CFPB, where the court ruled the Consumer Financial Protection Bureau’s leadership structure was unconstitutional, he articulated his desire to “repudiate” the “erroneous precedent” of Humphrey’s.
Several cases from the court’s emergency docket, or shadow docket, in recent months indicate that other justices share that desire. Such cases do not require full arguments but can indicate where the court is headed.
In Trump v. Wilcox, Trump v. Boyle and Trump v. Slaughter, all from 2025, the court upheld Trump’s firing of officials from the National Labor Relations Board, the Merit Systems Protection Board, the Consumer Product Safety Commission and the Federal Trade Commission.
Previously, these officials had appeared to be protected from political interference.
Remarks by conservative justices in those cases indicated that the court will soon reassess anti-unitary precedents.
In Trump v. Boyle, Justice Brett Kavanaugh wrote, “whether this Court will narrow or overrule a precedent … there is at least a fair prospect (not certainty, but at least a reasonable prospect) that we will do so.” And in her dissent in Trump v. Slaughter, Justice Elena Kagan said the conservative majority was “raring” to overturn Humphrey’s and finally officially embrace the unitary executive.
In short, the writing is on the wall, and Humphrey’s may soon go the way of Roe v. Wade and other landmark decisions that had guided American life for decades.
As for what judicial endorsement of the unitary executive theory could mean in practice, Trump seems to hope it will mean total control and hence the ability to eradicate the so-called “deep state.” Other conservatives hope it will diminish the government’s regulatory role.
Kagan recently warned it could mean the end of administrative governance – the ways that the federal government provides services, oversees businesses and enforces the law – as we know it:
“Humphrey’s undergirds a significant feature of American governance: bipartisan administrative bodies carrying out expertise-based functions with a measure of independence from presidential control. Congress created them … out of one basic vision. It thought that in certain spheres of government, a group of knowledgeable people from both parties – none of whom a President could remove without cause – would make decisions likely to advance the long-term public good.”
If the Supreme Court officially makes the chief executive a unitary executive, the advancement of the public good may depend on little more than the whims of the president, a state of affairs normally more characteristic of dictatorship than democracy.
Graham G. Dodds does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Being from Buffalo means getting to eat some of the best wings in the world. It means scraping snow and ice off your car in frigid mornings. And it means making a lifelong vow to the city’s NFL franchise, the Bills – for better or worse, till death do us part.
When I grew up in New York’s second-largest city, my community was bound together by loyalty to a football team that always found new ways to break our hearts. And yet at the start of each NFL season, we always found reasons to hope – we couldn’t help ourselves.
Coming from this football-crazed culture, I often wondered about the psychology of fandom. This eventually led me to pursue a Ph.D. in sport consumer behavior. As a doctoral student, I was most interested in one question: Is fandom good for us?
I found a huge body of research on the psychological and social effects of fandom, and it certainly made being devoted to a team look good. Fandom builds belonging, helps adults make friends, boosts happiness and even provides a buffer against traumatic life events.
While fandom appears to be a boon for our mental health, strikingly little research had been conducted on the relationship between fandom and physical health.
So I decided to conduct a series of studies – mainly of people in Western countries – on this topic. I found that being a sports fan can have some drawbacks for physical health, especially among the most committed fans.
Tailgating culture revolves around alcohol. Research shows that college sports fans binge drink at significantly higher rates than nonfans, are more likely to do something they later regretted and are more likely to drive drunk. Meanwhile, watch parties encourage being stationary for hours and mindlessly snacking. And, of course, fandom goes hand in hand with heavily processed foods like wings, nachos, pizza and hot dogs.
One fan told me that when watching games, his relationship with food is “almost Pavlovian”; he craves “decadent” foods the same way he seeks out popcorn at the movies.
Fans kick back to watch games at Caesars Palace Race and Sports Book in Las Vegas. George Rose/Getty Images
Inside the stadium, healthy options have traditionally been scarce and overpriced. A Sports Illustrated writer joked in 1966 that fans leave stadiums and arenas with “the same body chemistry as a jelly doughnut.”
Little seems to have changed since. One Gen Z fan I recently interviewed griped, “You might find one salad with a plain piece of lettuce and a quarter of a tomato.”
Eating away the anxiety and pain
The relationship between fandom and physical health isn’t just about guzzling beer, sitting for hours on end or scarfing down hot dogs.
One study analyzed sales from grocery stores. The researchers found that fans consume more calories – and less healthy food – on the day following a loss by their favorite team, a reaction the researchers tied to stress and disappointment.
Emotions like anger, sadness and disappointment lead to stronger cravings. And this relationship is tied to how your favorite team performs when it matters most. For example, we found that games between rivals and closely contested games yield more pronounced effects. Emotional states generated by the game are also significantly correlated with increased beer sales in the stadium.
High-calorie cultures
In another paper, my co-authors and I found that fans often feel torn between their desire to make healthy choices and their commitment to being a “true fan.”
Every fan base develops its own culture. These unwritten rules vary from team to team, and they aren’t just about wearing a cheesehead hat or waving a Terrible Towel. They also include expectations around drinking, eating and lifestyle.
These health-related norms are shaped by a variety of factors, including the region’s culture, team history and even team sponsorships.
For example, the Cincinnati Bengals partner with Skyline Chili, a regional chain that makes a meat sauce that’s often poured over hot dogs or spaghetti. One Bengals fan I interviewed observed that if you attend a Bengals game, sure, you could eat something else – but a “true fan” eats Skyline.
I have two studies in progress that show how hardcore fans typically align their health behaviors with the health norms of their fan base. This becomes a way to signal their allegiance to the team, improve their standing among fellow fans, and contribute to what makes the fan base distinct in the eyes of its members.
Cheese and sausages are synonymous with Wisconsin – and being a fan of the state’s NFL team, the Green Bay Packers. Jeff Haynes/AFP via Getty Images
In Buffalo, for example, tailgating often revolves around alcohol – so much so that Bills fans have a reputation for over-the-top drinking rituals.
And in New Orleans, Saints fans often link fandom to Louisiana food traditions. As one fan explained: “People make a bunch of fried food or huge pots of gumbo or étouffée, and eat all day – from hours before the game until hours after.”
A new generation of health-conscious fans
The fan experience is shaped by the culture in which it is embedded. Teams actively help shape these cultures, and there’s a business argument to be had for teams to play a bigger role in changing some of these norms.
If stadiums and tailgates continue to revolve around beer and nachos, why would a generation attuned to fitness influencers and “fitspiration” buy in? To reach this market, I think the sports industry will need to promote its professional sports teams in new ways.
Some teams are already doing so. The British soccer team Liverpool has partnered with the exercise equipment company Peloton. Another club, Manchester City, has teamed up with a nonalcoholic beer brand as the official sponsor of its practice uniforms.
And several European soccer clubs have even joined a “Healthy Stadia” movement, revamping in-stadium food options and encouraging fans to walk and bike to the stadium.
For the record, I don’t think the solution is replacing typical fan foods with smoothies and salads. Alienating core consumers is generally not a sound business strategy.
I think it’s reasonable, however, to suggest sports teams might add more healthy options and carefully evaluate the signals they send through sponsorships.
As one fan I recently interviewed said: “The NFL has had half-assed efforts like Play 60” – a campaign encouraging kids to get at least 60 minutes of physical activity per day – “while also making a ton of money from beer, food and, back in the day, cigarette advertisements. How can sports leagues seriously expect people to be healthier if they promote unhealthy behaviors?”
Today’s consumers want to support brands that reflect their values. This is particularly true for Gen Zers, many of whom are savvy enough to see through hollow campaigns and quick to reject hypocrisy. In the long run, I think this type of dissonance – sandwiching a Play 60 commercial between ads for Uber Eats and Anheuser-Busch – will prove counterproductive.
Relish, ketchup and mustard ‘race’ during a September 2025 baseball game between the Kansas City Royals and Seattle Mariners, in an encapsulation kind of dissonance between showcasing both physical activity and junk food at sporting events. Scott Winters/Icon Sportswire via Getty Images
I, as much as anyone else, understand what makes fandom special – and yes, I’ve eaten my share of wings during Bills games. But public health is a pressing concern, and though the sports industry is well-positioned to address this issue, fandom isn’t helping. Actually, my research suggests it’s having the opposite effect.
Striking the balance I’m advocating will be tricky, but the sports industry is filled with bright problem-solvers. In the film “Moneyball,” Brad Pitt’s character, Billy Beane, famously says sports teams must “adapt or die.” He was referring to the need for baseball teams to integrate analytics into their decision-making.
Professional sports teams eventually got that message. Maybe they’ll get this one, too.
Aaron Mansfield does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
As a tribal member of Spirit Lake Nation in North Dakota and the former president of Cankdeska Cikana Community College in Fort Totten, North Dakota, I recognize the difference that tribal colleges and universities, like the one I used to work at, can have in rerouting Native students’ education journeys.
Tribal colleges and universities, or TCUs, are public institutions that are founded and run by a Native American tribe and focus on serving Native American students and communities.
There are 35 accredited TCUs across 13 states, including Montana, Arizona, Oklahoma, North Dakota and South Dakota. All of these schools are nonprofits.
While a single Native tribe sometimes sets up a tribal college, in other cases a consortium of tribes or the federal government helps establish a school.
Despite their differences, tribal colleges and universities all have the same mission of teaching Indigenous history, culture and languages.
All the tribal colleges also offer associate degrees and certifications. Twenty-two of them have only baccalaureate programs, and nine have master’s programs. Navajo Technical University, a tribal college in Crownpoint, New Mexico, which has the largest enrollment size of all the TCUs, began offering a first of its kind doctorate program in Diné Studies in 2024. This program focuses on the language, culture and history of the Diné people, also known as Navajo people.
TCUs keep their tuition relatively low in part because a majority of their funding comes from the federal government. They also receive funding from philanthropic organizations.
TCUs also generally have minimal overhead costs, since most students live off-campus and only a handful of these colleges and universities offer on-campus housing. Most TCUs have both in-person and online courses.
While there is no single profile of a TCU student, I found that it is common to encounter a 30-year-old, single mother who works full time while trying to earn a college degree.
Several factors prevented most Native American students from attending a college or university.
The cost of college was prohibitive, and many Native American students were also not adequately prepared for college in high school. These students and their families also feared that higher education could force them to assimilate into Western and white culture, and erase their own Native traditions and languages.
A long political relationship
When considering this historical context, it is important to understand that Native Americans have a unique relationship with the federal government.
Native Americans largely consider this relationship a political one, bound by the various legal precedents, federal policies and executive orders from the 1800s and onward. These orders and policies from the past several hundred years vary, but they often focus on questions of land, assimilation and the political independence of Native tribes.
Alongside the creation of new tribal colleges and universities over the past several decades, more and more Native people living on reservations have graduated from high school and received higher education degrees.
The percentage of Native college graduates rose 125% from 1990 to 2020. While 4.5% of Native students living on reservations received a college degree in 1990, that percentage rose to 10.3% with at least a college degree in 2020, according to findings by Harvard Kennedy School in September 2025.
Yet, unlike the high school trends, Native people still graduate college at a much lower rate than the general American population.
In 1990, 20.3% of all Americans had at least a college degree. In 2020, 34.3% of Americans had a college degree at a minimum, according to the Harvard Kennedy School findings.
A professor at Navajo Technical University participates in a veterinary technology program conducted with the Department of Agriculture in 2019 in Crownpoint, N.M. Flickr/U.S. Department of Agriculture, CC BY
A lasting impact
While tribal colleges and universities receive state and federal funding, they are chronically underfunded and often operate in survival mode. In some cases, they lack money to make needed repairs on campus buildings.
One major reason for this shortfall: While Congress agreed in the late 1970s to annually give tribal colleges $8,000 for each Native student they enroll, it has not met this financial and political commitment.
Tribal colleges annually receive $250 million less than what the federal government promised them, a 2024 ProPublica investigation found.
Tribal college and universities’ futures were cast in doubt in the spring of 2025, when the Trump administration announced a proposal to cut the Bureau of Indian Education’s annual budget from $183 million to $22 million. The Bureau of Indian Education is part of the Department of the Interior and oversees education for Native students.
But the Department of Education went on to announce in September that it would make a one-time, $495 million investment in historically Black colleges and universities and TCUs.
I think it is important to recognize that TCUs make broad contributions to society, well beyond the impact they have on individual students.
TCUs teach entrepreneurship and business development and serve as pilot sites in launching businesses, for example.
For every federal dollar invested in tribal colleges, the schools return $1.60 in tax revenue through the increased tax payments of their alumni and their alumni’s employers, according to a September 2025 report by the American Indian Higher Education Consortium, a national organization that represents TCUs.
TCU alumni also generated $3.8 billion in added income, or gross domestic product, to the national economy from October 2022 through September 2023.
These schools offer a unique pathway for Native students to attend a higher education institution, while teaching them the skills they need to build a stable career.
I served as President of Cankdeska Cikana Community College (CCCC) one of the 34 tribal colleges located in North Dakota and that is affiliated with AIHEC. I am a member of the Spirit Lake Dakota Tribe who chartered CCCC in the 1970s. As a tribal college President, I served on the AIHEC Board of Directors and its Executive Committee.
Source: The Conversation – USA (2) – By Rohan Shah, Assistant Professor of Economics, University of Mississippi; Institute for Humane Studies
Welcome back: The number of young adults living with their parents has risen by 1.5 million over the past decade.Maskot/DigitalVision via GettyImages
A potentially worrisome trend is emerging among young adults. Instead of landing a job and moving to the big city after graduation, many are moving back into their childhood homes instead. About 1.5 million more adults under 35 live with their parents today than a decade ago. That’s a 6.3% jump, more than double the rate of growth for the young adult population overall.
The issue is affordability. Over the past decade, urban rents have climbed about 4% per year, while wages for full-time workers have increased by only 0.6% annually. That means it’s harder than ever to live in a big city on the typical salary – especially if you’re a new graduate without much work experience.
The situation is even more challenging for aspiring homeowners: The median house price in the U.S. has risen about 90% in just 10 years, or more than 6% each year. And as prices rise – the median home sells for more than $400,000 now – so too do the ages of homebuyers. The median first-time U.S. homebuyer is 38 years old, up from 31 about a decade ago.
Why is the rent so high?
Put simply, there isn’t enough housing. As an economist, I know that when demand rises faster than supply, prices have to increase. And supply is severely limited in the places where people most want to live: big cities such as New York and San Francisco.
In most of these cities, planning and zoning laws prevent developers from building enough to meet demand. For example, rezoning a plot of land from commercial to residential often requires mountains of paperwork. And in many cities, objections from neighbors can stall a proposed development. These are just two of many obstacles local governments throw in homebuilders’ way.
One city that has tried something different is Austin, Texas. After deliberately relaxing its zoning laws a few years ago, Austin has seen a boom in home construction. Rents fell by 10% in one year and by as much as 22% in two years after that change. By making it easier to build, Austin has made it cheaper to live there.
I don’t think it’s a coincidence that Austin has a far lower share of its young adults living with their parents than many other cities do. Just 6% of working adults in the Austin metro area live with their parents, one analysis found, versus nearly 14% in Greater San Antonio and 20% in Greater Los Angeles.
The pros and cons of living with the ’rents
One obvious advantage of living with parents is that they tend to charge below-market rents, or nothing at all. That makes it easier to save for a deposit on a house, helping young adults get on the property ladder sooner than they would otherwise. Indeed, homeownership rates among those 25 to 34 have risen slightly since 2016.
There are also potential disadvantages, however, particularly when it comes to socializing. Living at home with parents can make it much more challenging to meet new people. This, in turn, could partly help explain why Americans are getting married and having children later in life. These delays might not seem important, but they can leave people feeling like they’re behind in life, which can affect their health and well-being.
The housing shortage isn’t just an issue for young adults. A recent analysis I found insightful was headlined “The housing theory of everything.” It argued that the issue helps explain at least part of the current malaise in the U.S. economy.
For example, when people can’t live and work where they want, they’re unable to use their talents fully. That contributes to the relatively slow productivity growth the U.S. has experienced in recent years.
Similarly, if people can’t live in areas where they might meet and work with like-minded individuals, they have fewer opportunities to share ideas, which can hinder innovation.
And if the housing shortage is indeed encouraging young adults to delay having children, it could make it harder for the U.S. to fund Social Security and other government programs in the future.
Making it easier to build new homes in places people want to live and work could go a long way to easing these problems. It’s possible high rents translate into high barriers to adulthood, too.
I am acquaintances with the authors of the article “The Housing Theory of Everything.”
More than three-quarters of U.S. counties and jurisdictions are experiencing declines in childhood vaccination rates, a trend that began in 2019, according to a September 2025 NBC News–Stanford University investigation. The report also found a “large swath” of the U.S. no longer has the “basic, ground-level immunity” needed to stop the spread of measles.
Dr. David Higgins discusses back-to-school vaccinations.
The Conversation has collaborated with SciLine to bring you highlights from the discussion, edited for brevity and clarity.
What vaccines are typically required for schoolchildren, and why?
David Higgins: The vaccine requirements for kids to attend school are set by states, not the federal government. Most states require kindergartners get vaccines for pertussis – that’s whooping cough – and tetanus, measles, mumps, rubella and chickenpox.
For older kids, a booster of the tetanus and pertussis vaccine is typically required, as well as a vaccine for meningococcal disease.
How do scientists track the safety of vaccines over time?
Higgins: Before vaccines are approved, they undergo rigorous trials. During this process, scientists look at the safety and effectiveness of the vaccine, testing it first in small groups to assess safety, then in larger groups to confirm protection and detect uncommon side effects. That process continues after the vaccine is approved. Those systems continually monitor the safety of vaccines, both here in the U.S. as well as around the world.
What are the vaccination coverage trends for kindergartners?
Higgins: What we have seen is a small downward trend since 2019, the year prior to the COVID-19 pandemic. It slipped from 95% of new kindergartners being up to date on many of their routine vaccines to about 92%.
That’s a small percentage decrease, so a great majority of parents are still vaccinating their kids. But at the same time, anything below our target of 95% for diseases like measles becomes a problem, because that’s below the level that’s needed for what we call herd immunity, or community immunity. When that happens, it’s not a matter of if, but when, we see an outbreak of these infectious diseases.
And while nationwide rates are important to look at, outbreaks happen at local community levels. For example, earlier this year, an outbreak of measles in West Texas spread rapidly through communities where vaccination rates had slipped well below the state average.
So, the vaccination rate at your own school or community is much more meaningful than what the national vaccination rate is.
How do non-medical vaccine exemptions work?
Higgins: First, actual medical exemptions are rare, and these occur when the vaccine is unsafe for the child to receive, like when he or she has a known severe allergic reaction to vaccine ingredients.
Additionally, vaccines are victims of their own success. They have worked so well that many diseases like polio aren’t routinely seen anymore. That might lead a parent to think the risk for their child is so low that the vaccine is not necessary. But the fact is, vaccines are simply holding these diseases at bay. And as vaccination rates drop, these diseases will come back and more kids will be at risk.
What advice do you have for parents?
Higgins: The most important thing you can do as a parent is to keep your kids up to date on required vaccines. That includes the annual flu shot. Follow your state’s requirements and current recommendations from trusted sources like the American Academy of Pediatrics and your own personal pediatrician to know which vaccines your child should have.
You also want to reinforce other common sense approaches to keeping your children healthy. Make sure they know how to wash their hands properly and that they stay home when they’re sick. Teach them to sneeze and cough into their elbow instead of into their hands – even though doing so isn’t a perfect solution.
As a pediatrician, I love when my families come and talk to me about their concerns. I help them walk through their worries so they can feel more confident that they’re making a truly informed decision that’s in the best interest of their child’s health.
SciLine is a free service based at the American Association for the Advancement of Science, a nonprofit that helps journalists include scientific evidence and experts in their news stories.
David Higgins is a member of the American Academy of Pediatrics. He is also on the board of directors (volunteer) for Immunize Colorado.
In October 2025, Cecil Roberts will officially retire from his role as president of the United Mine Workers of America. A sixth-generation coal miner, he has led the union for 30 years. Only one man held the role longer: John L. Lewis, whom many consider one of the most important labor leaders of the 20th century.
Roberts has seen the union through an especially difficult period for the coal industry and grew up immersed in it. He was raised in Cabin Creek, West Virginia, where his great-grandmother – an activist in her own right – let miners camp on her property during a legendary strike in 1912. Bill Blizzard, his great-uncle, led miners during the Battle of Blair Mountain, the largest labor uprising in U.S. history. Both of his grandfathers died in mine accidents.
And there’s another way Roberts is steeped in Appalachian history: Before an audience of workers, observers have often noted, he speakslikeapreacher. Roberts likens miners’ struggles to biblical stories, references the power of God and the teachings of Jesus, and speaks in the dynamic cadences found in an Appalachian church.
United Mine Workers of America President Cecil Roberts speaks to about 4,000 retired members in Lexington, Ky., on June 14, 2016. AP Photo/Dylan Lovan
“Be like Jesus,” he told a rally in Charleston, West Virginia, in 2015, opposing a “right to work” bill that allowed workers in union-run shops to opt out of paying dues. “Jesus saw the money changers in the temple, and Jesus drove the money changers from the temple. So let me tell the National Right to Work Committee, the Chamber of Commerce, the Koch Brothers, and all those who gave money: you got your money’s worth, but we’re not for sale in West Virginia.”
“How many of you have been to a Baptist church? We’re going to take up a collection. It is altar call time,” he continued. “Now, I’m going to ask you something: Are you fed up? Let me hear you say, ‘Fed up.’… Are you so fed up that you are now fired up? Let me hear you say, ‘Fired up!’”
Capping off the rousing call-and-response, he shouted, “God bless all of you, you’re the salt of the earth!”
In the 1880s, two groups rushed into the central Appalachian Mountains: industrialists seeking coal, and missionaries seeking moral reform. Both changed the region forever, and their stories were intertwined.
At the time, central Appalachia was widely depicted in the popular press as a backward, ignorant region whose mountainous terrain kept its people isolated, outside the flow of progress – a stereotype still common today. Equating economic progress with moral progress, many Americans assumed that developing industry would lift people out of what they perceived as fatalism and superstition.
The coal industry used this idea to promote its rapid exploitation of mountain resources. Companies built railroads to connect the region to the national market, developed industrial coal mines and reshaped the central Appalachian economy. Missionaries opened churches, schools and camps.
Henry Ford founded Twin Branch, W.Va. – shown here in the 1920s – as a town for coal miners. Bettmann via Getty Images
Company-owned coal towns encompassed miners’ lives. People who had long farmed for themselves and lived, as the Bible told them to, “by the sweat of their brow,” became dependent upon coal companies as mine development shrank the size of family farms. Not only did employers own the miners’ houses, but they also paid workers in “scrip,” which was redeemable only at the company store.
Many company towns included theaters, offered films and music, and even built churches and paid pastors’ salaries. These were typically mainline Protestant churches, such as Methodist or Presbyterian.
To some Appalachian natives, these denominations were known as “railroad religion” because of the way they entered the mountains. And, for many miners, these were the churches of management. When there was labor unrest, the coal town churches tended to side with the companies, advising miners against strikes or agitation.
Pastors preached about the dangers and sacrifices miners faced deep underground, in an age of few regulations. God was on the side of the oppressed and downtrodden, they stressed – and those who gained at others’ expense would ultimately face divine judgment.
Their passionate preaching was meant to inspire action, whether it was committing one’s life to Jesus or to the union. Labor rights were deeply understood as religious issues, rooted in Christian concerns for justice and care.
John Sayles’ 1987 film “Matewan” powerfully depicted the divided role that religion played in West Virginia’s coalfields. One preacher, played by Sayles, equates the union with “the Prince of Darkness.” Another, a young miner, advocates in biblical terms for the union’s righteousness and helps to lead a strike. The result was the Matewan Massacre of 1920: a bloody battle between miners and armed guards hired by the mine owners.
Miner preachers and independent churches were central to the organization of miners in eastern Kentucky in the 1930s, too, during another period of violence between mine operators and miners over conditions, wages and unionization. It was during this time that miner’s wife and singer Sarah Ogan Gunning penned “Dreadful Memories,” turning the traditional hymn “Precious Memories” into a visceral depiction of miners’ struggle and a call for unionization:
“Dreadful memories, how they linger,
How they ever flood my soul.
How the workers and their children
Died from hunger and from cold.”
Today, it is still not surprising to find religious – particularly Christian – rhetoric in labor organizing. United Auto Workers President Shawn Fain is another example of a union leader whose speeches draw from the Bible.
But the dynamics of religion and class forged by industrial mining have shaped central Appalachia’s culture in lasting ways particular to the coalfields. The history of labor struggle, infused with religious idioms, is a source of identity and values evident in everything from union meetings in churches to prayers on picket lines.
Today, the United Mine Workers of America is focused less on coal itself, which miners know cannot last forever. The union represents members in other sectors, too, including public employees, manufacturing, health care and employees of the Navajo Nation. It has also focused its work on an equitable transition to renewable energy: one that accounts for the economic, cultural and environmental destruction that a single-industry economy has wreaked on central Appalachia.
Likewise, the United Mine Workers of America has fought to hold coal companies to their pension and health care obligations toward retired and sick miners whose work fueled the country and made companies rich.
And that struggle, Roberts would say, is a religious one as well.
Richard J. Callahan, Jr. does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Source: The Conversation – in French – By Jérémy Hamon, Chargé d’études en toxicovigilance – Direction des alertes et des vigilances sanitaires, Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail (Anses)
Depuis le 1er juillet 2025, 500 intoxications dues à la cueillette et à la consommation de champignons sont déjà à déplorer en France. On observe une augmentation des cas depuis le début du mois de septembre, et un pic est attendu en octobre. Pour identifier les champignons avec certitude, l’Agence nationale de sécurité sanitaire rappelle qu’il ne faut pas se fier aux applications sur smartphone, en raison du risque élevé d’erreurs. On fait le point sur l’ensemble de ces recommandations de l’Anses.
En France, plus de 3 000 espèces de champignons dits « supérieurs » ou « macromycètes » sont recensées. Si les champignons sont des aliments appréciés, certaines espèces sont toxiques voire mortelles pour l’humain. Ainsi la confusion entre une espèce comestible et une espèce toxique peut conduire à une intoxication, parfois grave.
Les intoxications par ingestion de champignons peuvent aussi résulter de la consommation de champignons réputés comestibles contaminés par des microorganismes (bactéries, parasites…), par des polluants chimiques ou bien parce qu’insuffisamment cuits.
Avant la cueillette, les bonnes pratiques à suivre :
Prévoir un panier en osier, une caisse ou un carton pour déposer ses champignons. Sa taille doit être suffisamment grande pour séparer les différentes espèces. Surtout, ne jamais utiliser de sacs en plastique, ils accélèrent le pourrissement ;
Choisir un lieu de cueillette loin des sites pollués (bords de route, aires industrielles, décharges, pâturages) ;
Se renseigner sur les structures qui peuvent aider à identifier une cueillette en cas de doute : certains pharmaciens ou les associations de mycologie de votre région.
Une surveillance saisonnière par les autorités de santé
L’Agence nationale de sécurité sanitaire de l’alimentation, du travail et de l’environnement (Anses) réalise chaque année, depuis 2016, une surveillance des intoxications accidentelles par ingestion de champignons.
Du fait de leur caractère saisonnier, de la température et de l’humidité conditionnant la pousse des champignons, cette surveillance des intoxications a lieu du 1er juillet au 31 décembre. L’Anses suit ainsi chaque semaine, avec l’appui du réseau des centres antipoison (CAP), le nombre d’intoxications qui leur est rapporté.
Chaque saison, entre 11 et 41 personnes intoxiquées ont un pronostic vital engagé, et entre 0 et 5 personnes intoxiquées décèdent.
Près de 4 % des intoxications enregistrées par les centres antipoison
Pour la saison 2024, le nombre d’intoxications (1 363) était légèrement inférieur à celui de 2023, mais sensiblement égal à ceux de 2021, de 2020 et de 2017. Le nombre de cas graves (41) était l’un des trois plus élevés (avec 2021 et 2017) depuis 2016 ; et le pourcentage de cas graves était d’environ 3 %, soit le deuxième pourcentage le plus haut, après 2021, depuis 2016 également. Le pic mensuel d’intoxications pour la saison 2024 est survenu en octobre, comme pour la plupart des années précédentes.
Depuis le début de la surveillance saisonnière en 2016, le nombre d’intoxications par an varie d’une année à l’autre, mais ne suit pas de tendance particulière (figure ci-dessous). Depuis 2017, ce nombre est supérieur à 1 000 et représente environ 4 % de l’ensemble des intoxications accidentelles enregistrées par les CAP.
Intoxications accidentelles par des champignons observés par les centres antipoison (CAP), de 2016 à 2024
Un questionnaire spécifique pour améliorer la prévention
Depuis 2022, un questionnaire de recueil spécifique est soumis à chaque personne appelant un CAP à la suite de la consommation de champignons dans un contexte alimentaire et présentant des symptômes. Ce questionnaire a pour but d’améliorer la connaissance des circonstances des intoxications et de cibler plus efficacement les messages de prévention. Les nouvelles données, ainsi récoltées, concernent le mode d’obtention des champignons, les espèces de champignons recherchées au cours de la cueillette, le mode d’identification, le mode de transport et le temps de conservation des champignons ainsi que le mode de consommation des champignons.
Ce questionnaire a permis de mettre en évidence, entre autres, les champignons les plus souvent recherchés. En 2022 et en 2023, les personnes intoxiquées ont déclaré qu’il s’agissait de cèpes (ou bolets), de coulemelles (ou lépiotes), et d’agarics champêtres (aussi appelés « rosés des prés »).
Pour la saison 2024, et probablement parce que la pousse des bolets et des agarics semble s’être arrêtée plus tôt que d’autres années, les rendant ainsi moins disponibles à la cueillette, ce sont les girolles (ou chanterelles) qui étaient les plus recherchées au cours de l’ensemble de la saison (et, plus particulièrement, à partir de la deuxième semaine d’octobre).
Cette différence a conduit à un nombre plus important de confusions avec des pleurotes de l’olivier (Omphalotus olearius) et des faux clitocybes lumineux (Omphalotus illudens), qui sont toxiques.
Pendant la cueillette, comment bien identifier les champignons ?
Ne pas se fier aux applications de reconnaissance sur smartphone, en raison du risque élevé d’erreurs d’identification ;
Ne ramasser que les champignons que vous connaissez parfaitement. Attention ! Des champignons vénéneux peuvent pousser à l’endroit où vous avez cueilli des champignons comestibles une autre année ;
Cueillir uniquement les spécimens en bon état et prélever la totalité du champignon (pied et chapeau) afin d’en permettre l’identification ;
Éviter de ramasser les jeunes spécimens qui n’ont pas fini de se former, ce qui favorise les confusions, et les vieux spécimens qui risquent d’être abîmés ;
Au moindre doute sur l’état ou sur l’identification d’un des champignons récoltés, ne pas consommer la récolte avant de l’avoir fait contrôler par un pharmacien ou par une association de mycologie.
Ressemblance entre espèces toxiques et espèces réputées comestibles
Depuis 2022, les autres espèces toxiques les plus souvent identifiées par les experts mycologues qui font partie d’un réseau national les mettant en relation avec les centres antipoison, étaient les agarics jaunissants, les lépiotes des jardins (ou lépiotes vénéneuses), les entolomes livides, les bolets Satan ou encore les amanites phalloïdes.
Ces espèces toxiques peuvent être mises en regard des espèces les plus recherchées : les agarics jaunissants et les amanites phalloïdes peuvent, en effet, être confondues avec des agarics champêtres, les bolets Satan peuvent être confondus avec des espèces de bolets comestibles, et les lépiotes des jardins avec des coulemelles.
Liste des espèces recherchées par les cueilleurs versus les espèces toxiques de champignons cueillis (identifiés par un expert mycologue), pour la saison 2024
Source : Sicap. Tableau extrait d’« Intoxications accidentelles par des champignons en France métropolitaine. Bilan des cas enregistrés par les centres antipoison entre le 1er juillet et le 31 décembre 2024 », Rapport d’étude de toxicovigilance, septembre 2025, Anses.
Groupe d’espèces recherchées
Espèce toxique cueillie (identifiée par un expert mycologue)
Agarics champêtres, rosés des prés
Agaric jaunissant (Agaricus xanthodermus)
Amanites des Césars (oronge)
Amanite tue-mouches (Amanita muscaria)
Cèpes ou bolets non précisés
Bolet Satan (Rubroboletus satanas)
Coulemelles, lépiotes
Lépiote des jardins (Chlorophyllum brunneum), amanite phalloïde (Amanita phalloides)
Girolles, chanterelles
Clitocybe de l’olivier (Omphalotus olearius), faux clitocybe lumineux (Omphalotus illudens)
Mousserons, faux mousserons (marasmes des oréades)
Lépiote de Josserand (Lepiota josserandii), galère marginée (Galerina marginata)
Ci-dessous, composition de trois espèces de champignons toxiques, après expertise par des experts mycologues
(Avertissement : ces photographies n’ont pas vocation à être utilisées pour une identification de champignons, ndlr.)
En haut : Amanite phalloïde (Amanita phalloides) ; en bas à gauche : Bolet Satan (Rubroboletus satanas) ; en bas à droite : Clitocybe de l’olivier appelé aussi Pleurote de l’olivier (Omphalotus olearius). (Holger Krisp/Antonio Abbatiello), CC BY
Certaines espèces toxiques de champignons peuvent ressembler fortement à des espèces comestibles. L’identification de l’espèce du champignon cueilli est donc une étape indispensable et très importante pour le cueilleur, et doit être réalisée par des personnes expertes sur le sujet (mycologue ou association de cueilleurs experts, par exemple). Les applications ou les fonctionnalités de reconnaissance d’image directement disponibles sur certains smartphones ne sont actuellement pas suffisamment performantes pour identifier correctement un champignon, et leur utilisation est donc déconseillée car sujette à des erreurs.
Enfin, le questionnaire disponible depuis 2022 a permis de mettre en évidence qu’environ les trois quarts des personnes intoxiquées n’avaient pas fait identifier leur cueillette. Une grande partie de ces intoxications auraient probablement pu être évitées si la cueillette avait fait l’objet d’une identification, idéalement par un expert mycologue ou par une association spécialisée.
Après la cueillette : quels gestes adopter ?
Se laver soigneusement les mains ;
Prendre une photo de votre récolte avant la cuisson : elle sera utile en cas d’intoxication pour décider du traitement adéquat ;
Conserver les champignons en évitant tout contact avec d’autres aliments au réfrigérateur (maximum 4 °C) et les consommer dans les deux jours qui suivent la cueillette ;
Ne jamais consommer les champignons crus, et cuire chaque espèce séparément et suffisamment longtemps : de 20 à 30 minutes à la poêle ou 15 minutes à l’eau bouillante avec rejet de l’eau de cuisson ;
Consommer les champignons en quantité raisonnable, soit 150 à 200 grammes par adulte et par semaine ;
Ne jamais proposer de champignons cueillis à de jeunes enfants ;
Ne pas consommer de champignon identifié au moyen d’une application de reconnaissance de champignons sur smartphone en raison du risque élevé d’erreur.
En moyenne, 2 % des intoxications par des champignons sont graves
Si la plupart des intoxications sont bénignes, reste qu’il est possible d’atteindre jusqu’à 41 « intoxications graves » par saison (soit un maximum de 3,2 % des intoxications saisonnières ; la moyenne étant de 2 % de 2016 à 2024).
Les intoxications sont considérées comme graves lorsque le pronostic vital du patient est engagé. Parmi ces intoxications graves, certaines sont mortelles et d’autres peuvent conduire à des insuffisances rénales ou hépatiques sévères devant parfois nécessiter une transplantation d’organe.
Les espèces toxiques de champignons ne produisent pas toutes les mêmes toxines et conduisent donc à des intoxications présentant des symptômes différents. L’ensemble de ces symptômes permet de déterminer le type de syndrome mycotoxique.
Concernant les intoxications graves, les syndromes mycotoxiques les plus fréquents sont les syndromes phalloïdien, orellanien et sudorien :
Le syndrome phalloïden, principalement causé par les amanites toxiques (amanite phalloïde et amanite vireuse, par exemple) et certaines petites lépiotes toxiques, est caractérisé par des symptômes digestifs suivis d’une atteinte hépatique pouvant être gravissime et conduire à une greffe de foie ;
Le syndrome orellanien, principalement causé par le cortinaire très joli et le cortinaire des montagnes, est caractérisé par des symptômes digestifs inconstants puis une atteinte rénale d’apparition plus tardive (entre 2 et 20 jours après l’ingestion du champignon) ;
Le syndrome sudorien, principalement causé par certains clitocybes blancs (clitocybe blanchi et clitocybe cérusé, par exemple), par un grand nombre d’inocybes et certains mycènes, est caractérisé par des troubles digestifs associés à des sueurs, à des larmoiements, à un myosis (diminution de la taille de la pupille) et à une diminution de la fréquence cardiaque et de la tension artérielle.
Prévention et recommandations
L’Anses diffuse chaque année, au moment des périodes de pousse et de cueillette des champignons, des messages de prévention dans la presse, sur les réseaux sociaux et dans certains établissements (les pharmacies, par exemple).
Si la diffusion de ces messages est nécessaire pour informer la population des recommandations nationales de cueillette et de consommation des champignons, des relais locaux (associations de mycologues, pharmaciens…) restent indispensables pour aider à identifier la cueillette et, ainsi, pour limiter le nombre d’intoxications.
Enfin, pour prendre en compte les intoxications dues aux champignons sauvages conservés au congélateur (et consommés entre janvier et juillet) ainsi qu’à certaines espèces printanières, la surveillance des intoxications aux champignons couvre l’année entière (de janvier à décembre) depuis janvier 2025.
Les auteurs ne travaillent pas, ne conseillent pas, ne possèdent pas de parts, ne reçoivent pas de fonds d’une organisation qui pourrait tirer profit de cet article, et n’ont déclaré aucune autre affiliation que leur organisme de recherche.
Peut-on vraiment faire revenir le dodo ? Colossal Biosciences s’en rapproche grâce à l’édition génétique, mais le projet se heurte à d’énormes défis scientifiques et écologiques.
La société américaine de biotechnologie Colossal Biosciences affirme être enfin parvenue à maintenir en vie, suffisamment longtemps en laboratoire, des cellules de pigeon pour pouvoir en modifier l’ADN – une étape cruciale vers son rêve de recréer le dodo.
Selon Colossal Biosciences, ces cellules, une fois modifiées, pourraient être introduites dans des embryons de poulets eux-mêmes édités génétiquement, transformant ces derniers en mères porteuses pour des oiseaux disparus depuis plus de trois siècles. Cette percée s’accompagne d’un calendrier audacieux. Ben Lamm, le directeur général de Colossal Biosciences, affirme que les premiers « néo-dodos » pourraient éclore d’ici cinq à sept ans.
Il évoque aussi un objectif à plus long terme : relâcher plusieurs milliers d’oiseaux sur des sites de l’île Maurice protégés de tout prédateur, là même où vivaient les dodos avant leur disparition. Cette promesse a contribué à faire grimper la valorisation de la start-up au-delà de dix milliards de dollars, selon le site de l’entreprise.
Presque tout ce que l’on sait sur l’édition génétique des oiseaux vient des recherches menées sur le poulet, dont les cellules germinales – à l’origine des spermatozoïdes et des ovules – se développent sans difficulté dans des cultures de laboratoire classiques. Les cellules de pigeon, elles, meurent généralement en quelques heures en dehors de leur organisme.
Colossal Biosciences affirme avoir testé plus de 300 combinaisons de facteurs de croissance – des substances qui stimulent la multiplication cellulaire – avant d’en trouver une réellement efficace. Ces cellules peuvent désormais être chargées de fragments d’ADN reconstitués et d’interrupteurs moléculaires contrôlant la forme du crâne, la taille des ailes et la masse corporelle.
Des zones manquantes
Si les modifications prennent, ces cellules altérées migreront vers les ovaires ou les testicules d’un embryon de poulet encore à un stade précoce de développement, de sorte que l’animal adulte pondra des œufs ou produira du sperme porteur du génome modifié.
Ce procédé pourrait donner naissance à un oiseau qui ressemble à un dodo, mais la génétique ne raconte qu’une partie de l’histoire. Le génome du dodo a été reconstitué à partir d’os et de plumes conservés dans des musées, et les zones manquantes ont été comblées avec de l’ADN de pigeon ordinaire.
Parce que l’espèce est éteinte et ne peut plus être étudiée, on ignore encore largement les gènes impliqués dans son comportement, son métabolisme ou ses défenses immunitaires. Reconstituer les régions connues de son ADN, lettre par lettre, nécessiterait des centaines de modifications distinctes. Le travail à accomplir serait d’une ampleur sans précédent, bien au-delà de tout ce qui a été tenté dans les programmes de sélection agricole ou de recherche biomédicale, même si Colossal Biosciences semble prête à investir massivement pour y parvenir.
Reste aussi la question du poulet porteur. Un œuf de poule pèse bien moins qu’un œuf de dodo. Dans les collections muséales, il n’existe qu’un seul œuf de dodo connu, d’une taille comparable à celle d’un œuf d’autruche. Même si un embryon parvenait à survivre aux premiers stades, il dépasserait rapidement la taille de la coquille et devrait éclore avant d’être complètement formé – comme un prématuré nécessitant des soins intensifs. Le poussin devrait donc recevoir une surveillance et des soins constants pour atteindre le poids historique du dodo, estimé entre 10 et 20 kilos.
« Remplacement fonctionnel »
Des poules « génétiquement réinitialisées », modifiées par édition du génome, ont déjà pondu avec succès des œufs appartenant à des races rares de poulets, démontrant que la gestation croisée par cellules germinales fonctionne en principe. Mais appliquer cette technique à une espèce disparue et de taille bien supérieure reste totalement inédit.
C’est pour ces raisons que de nombreux biologistes préfèrent parler de « remplacement fonctionnel » plutôt que de « désextinction ». Ce qui pourrait éclore serait un hybride : principalement un pigeon de Nicobar, enrichi de fragments d’ADN de dodo et incubé dans un œuf de poule. Mais parler de résurrection relève davantage du marketing que de la science.
Les promesses et la réalité
La tension entre promesse et réalité a marqué les précédents projets de Colossal Biosciences. Les loups sinistres (Aenocyon dirus) présentés en août 2025 se sont révélés être des clones de loups gris avec quelques modifications génétiques. Des experts en conservation ont averti que ce type d’annonces peut inciter la société à considérer l’extinction comme réversible, réduisant ainsi le sentiment d’urgence à protéger les espèces menacées.
Malgré tout, la percée réalisée sur les pigeons pourrait profiter aux espèces encore vivantes. Environ un oiseau sur huit est aujourd’hui menacé d’extinction, selon l’évaluation mondiale de 2022 de BirdLife International. La culture de cellules germinales offre un moyen de préserver la diversité génétique sans avoir à maintenir d’immenses populations captives, et éventuellement de réintroduire cette diversité dans la nature.
Si la technique s’avère sûre chez les pigeons, elle pourrait aider à sauver des oiseaux en danger critique, comme l’aigle des Philippines ou le perroquet à ventre orange d’Australie. La population sauvage de ce dernier ne compte plus qu’environ 70 individus et avait même chuté à seulement 16 en 2016.
Une porte-parole de Colossal Biosciences a déclaré que l’entreprise respecte ses jalons scientifiques, mais que l’obtention d’éléphants mères porteuses et de cellule-œuf appropriés pour leur projet de mammouth laineux « implique une logistique complexe échappant à notre contrôle direct » et que « nous accordons la priorité au bien-être animal, ce qui signifie que nous ne précipitons aucune étape cruciale ».
Elle a ajouté que, selon les recherches de l’entreprise, les travaux de désextinction accentuent au contraire l’urgence de protéger les espèces menacées. « L’important, c’est que nous ne remplaçons pas les efforts de conservation existants, nous y ajoutons de nouvelles ressources et renforçons l’implication du public », a-t-elle précisé.
Un dodo irrécupérable
« Notre travail apporte des financements entièrement nouveaux à la conservation, provenant de sources qui n’investissaient pas auparavant dans la protection de la biodiversité. Nous avons ainsi attiré plusieurs centaines de millions de dollars de capitaux privés qui n’auraient autrement pas été consacrés à des projets de conservation. De plus, les outils génétiques que nous développons pour la désextinction sont déjà utilisés aujourd’hui pour aider des espèces menacées. »
Pour qu’un retour d’oiseaux proches du dodo soit possible sur l’île Maurice, il faut d’abord qu’y soit réunies les conditions fondamentales pour leur conservation. Il sera nécessaire d’éradiquer les rats, qui s’attaquaient aux dodos, de contrôler les populations de singes et de restaurer la forêt. Ces actions demandent des financements et l’adhésion des populations locales, mais elles bénéficient immédiatement à la faune encore présente. Colossal Biosciences devra respecter son engagement envers une gestion écologique durable.
Mais, au sens strict, le dodo du XVIIe siècle est irrécupérable. Ce que le monde pourrait voir d’ici à 2030 n’est qu’une expérience vivante, illustrant les avancées de l’édition génétique. L’intérêt de cet oiseau ne résidera pas dans la convocation du passé mais dans sa capacité à aider les espèces actuelles à ne pas connaître le destin du dodo.
Timothy Hearn ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d’une organisation qui pourrait tirer profit de cet article, et n’a déclaré aucune autre affiliation que son organisme de recherche.