About half of the reindeer and armadillos in Iowa are extinct. Here’s how animals are weathering the warm holidays

Not a particularly white Christmas this year. Across the United States, families gather to enjoy hiking on warm, sunny days. The fingerprints of climate change are all over the 2025 holiday season, and we at CNN thought it would be a good time to find out how the animals that shape our stories and traditions are weathering the warming.

From Santa’s reindeer and Hanukkah armadillo to some very festive sea worms, our changing world is changing lives for creatures big and small. And while some of these animals are struggling, some may be critical to helping us adapt in the future.

Reindeer cannot handle this temperature

You would think that a species that has already survived one of the most intense and rapid Arctic warming events in history would be well suited to weather modern, human-driven climate change. Unfortunately, things don’t look good for the reindeer, who may soon become as legendary as Santa’s elves.

Reindeer survived rapid warming during the last great ice age, 20,000 years ago. In Greenland, temperatures have risen by 18 degrees Fahrenheit in a few decades, pushing other arctic megafauna to extinction. But in the last 30 years, about 40% of the global reindeer population has disappeared. According to a study published in August by researchers from Australia’s University of Adelaide and the University of Copenhagen, the adaptations that served the species well in the past appear to be no longer as effective as they are today.

Those scientists found that reindeer survived previous changes in climate because they spread into many different ecological niches. They can thrive in small, cool shelters and repopulate larger areas when things cool down again.

Today, however, warming is global; The range of the reindeer is not so great; And it’s hard to find a warm place to plop down. Incorporating these findings about the past into a model of the future, the researchers found that the global population of reindeer could shrink by 58% between now and 2100 – with places like North America likely to lose even more.

Unfortunately, new research shows that fewer reindeer may actually make climate change worse. Researchers in Finland and Alaska found that, in remote northern forests where snow doesn’t fall as much as it used to, the soil releases more carbon dioxide into the atmosphere instead of storing it. But reindeer can resist that effect. If the reindeer are grazing under the trees, the soil still traps carbon – even if there is no snow.

Christmas tree insects can help us protect corals

The Christmas tree worm looks like a Christmas tree – but you’ll find it in a Kodachrome photo from a 1950s magazine. Conical, feathery and brightly colored in blues, pinks, plums and oranges, these tiny worms attach themselves to coral reefs as larvae and then hang around, motionless for the rest of their lives.

While they are not particularly active, they are far from lazy. Christmas tree worms have a symbiotic relationship with the coral they live on.

Tendril-shaking adult worms move the water around the coral, which helps feed the coral. And baby coral polyps find shelter under Christmas tree branches, where they can hide from predators like sea stars. Because of this, scientists think we may be able to use Christmas tree worms as a way to learn about coral health.

For example, a 2022 study by students at the University of California Berkeley found a correlation between healthy corals and higher numbers of Christmas tree insects. It’s possible that, in the future, these insects could become early warning signs — showing scientists where corals are under stress from warming oceans before the situation becomes serious.

Hanukkah armadillos are coming to your town

Back in 2000, when Ross from “Friends” dressed up as an armadillo to teach his son the true meaning of Hanukkah, the real-life animal was still thought of as a creature of the Southwest. But that has changed.

First identified in Texas in 1849, the nine-banded armadillo expanded its range significantly, tracing its steps to warmer climates north and east of its historic homeland. A survey conducted in 2014 found that the animals were able to establish footholds anywhere in January when the average low was above 18 degrees Fahrenheit.

Turns out, that describes a lot of the United States. Take Iowa for example. That state didn’t even have a confirmed report of a live armadillo until 2017. But in 2025, U.S. Geological Survey researchers used public wildlife reporting apps, live tracker cams and other data sources to document more than 250 recent armadillo sightings in Iowa.

Their data found hundreds of armadillos happily digging up gardens as far north as Indiana and as far east as North Carolina. Statistics are teaching us about what makes good armadillo country — warm, but not too dry, and forested at best — and where they’re likely to expand next — Ohio, Virginia and Michigan are all good candidates.

Narwhals live in surprising ways

In 2007, a young researcher approached the curator of Rosenborg Castle Museum in Denmark with a strange request. She wanted to enter the king’s throne.

The museum houses Denmark’s Coronation Chair, which was used by actual Danish kings from 1671 to 1840. But what was special about Eva Garde were the curly narwhal tusks that adorned the sides of the throne. Garde’s research focuses on the history and future sustainability of narwhals, a species of arctic toothed whale beloved by both young children and Buddy the Elf.

But narwhals, as a group, are not very genetically diverse—a fact that could prove dangerous for them because it would limit their ability to adapt to the warming Arctic. Garde wanted to know what Norval’s ancestors were like. And the DNA samples drilled from the 350-year-old throne were a great place to start. Perhaps, if Mr. Narwhal could find his father as Buddy did, then humans would have a better understanding of how to keep the species healthy in the future.

The museum allowed Garde to remove the specimens from the throne, and the whole thing was reassembled. Since then, his team has learned a lot about these creatures. In fact, his research has helped establish that narwhals have been living comfortably with low genetic diversity for thousands of years—which is surprising.

That doesn’t mean climate change isn’t a threat to narwhals. Genetic data suggest that this species may now be stable with the lowest diversity. If a warming Arctic reduces it further, the narwhal could be in trouble.

The pheasant is dying after a thousand cuts

Sending your true love a pheasant in a pear tree can be an invitation to hunt a small easy target. Red-legged pheasants have been a favorite game bird in Europe for millennia; Its bones are also found in Paleolithic settlements.

But the long association with humans has put the red-footed pheasant on the path to various negative impacts. It is over-hunted; Crushed by tractors and other modern farm equipment; sickened and killed as a side effect of agricultural pesticides; Former farmers have left the countryside for city work; and outcompeted by other species of pheasant bred specifically for hunting.

Between 2010 and 2020, red-legged partridge populations have declined by about 40-45%, according to the International Union for Conservation of Nature and Natural Resources, the organization that determines whether a species is endangered.

It has nothing to do with climate change in particular. But all this makes pheasants more vulnerable to climate change in the long term.

In 2021, a team led by scientists from Sweden and Italy sequenced the red-footed partridge genome and learned a few key things. First, this bird did not fare well during the warming event 140,000 years ago. In fact, its population declined so significantly during that time that its genetic diversity has never recovered. And unlike narwhals, which grew in population and remained stable with little genetic diversity, pheasants had no such fate.

The result is a bird that is ill-equipped to adapt to climate change and whose numbers are already declining, further reducing its ability to adapt.

Donkeys bring blessings on their backs

Las Posadas is a Central and South American Christmas tradition where people re-enact the story of Mary and Joseph finding the inn. Given their prominent role in biblical transportation, donkeys are a big part of the festival.

And research shows that donkeys have a role to play in helping people adapt to climate change. In northern Kenya and southern Somalia, for example, they are used to carry water and food over long distances during droughts. Other animals can do that in good times, but donkeys are particularly adept at helping humans survive climate disasters, a team of University College London researchers wrote in a recent book on Animal-Human Interactions under Climate Change. A donkey’s digestive system works like an internal saddle bag – absorbing excess water when available and holding onto that moisture when water is scarce. Because of this, they are able to continue to carry water and food to humans even when other animals cannot.

Donkeys also help support healthy ecosystems. Other grazing animals easily digest sensitive soils, leaving them vulnerable to erosion. But donkeys eat a wide variety of plants, so they are less likely to overindulge in grasses. And a recent report by Tunisian researchers suggests that Mediterranean donkeys prefer to eat invasive plants, which help different species thrive.

Donkeys also have the potential to help protect us from insects and the diseases they carry. Ticks and tick-borne diseases are increasing their range due to warmer weather. But a new study conducted by the University of Massachusetts in Amherst has found that the donkey’s skin releases chemicals that prevent ticks. When the chemicals were applied to the horses, the ticks stopped biting them too.

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