Nearly half of reindeer have been wiped out and armadillos are in Iowa. Here’s how animals are weathering warming holidays

It’s not going to be a particularly white Christmas this year. Across America, families gather together to enjoy walks on warm, sunny days. With the signs of climate change all over the 2025 holidays, we at CNN thought it would be a good time to look at how the animals that shape our stories and traditions are weathering the warmer weather.

From Santa’s reindeer and Hanukkah armadillos to some very festive sea insects, our changing world is changing the lives of creatures big and small. While some of these animals are struggling, some may hold the key to helping us adapt for the future.

Reindeer can’t cope with this warming

You might think that a species that has already survived the strongest and most rapid Arctic warming event in history would have enough to withstand modern human-driven climate change. Unfortunately, things are not looking good for the reindeer, who will soon become as mythical as Santa’s elves.

When the last big ice age melted about 20,000 years ago and the climate rapidly warmed, reindeer survived. In Greenland, temperatures soared 18 degrees Fahrenheit in just a few decades, leading to the extinction of other Arctic megafauna. But in the past 30 years, about 40% of the world’s reindeer population has disappeared. A study published in August by researchers at Australia’s University of Adelaide and the University of Copenhagen showed that the species’ last adaptation no longer appears to be as effective.

These scientists found that caribou have survived previous climate changes because they have spread into many different ecological niches. They can thrive in small, cool shelters and repopulate a wider area when the weather gets cold again.

Today, however, climate warming is global. Reindeer don’t have as much range; and it’s harder to find a cool place to hunker down. Incorporating these findings about the past into future models, the researchers found that global caribou populations could decline by 58% between now and 2100, with regions like North America suffering even greater losses.

Unfortunately, new research suggests that reducing caribou may actually make climate change worse. Researchers from Finland and Alaska have found that in far northern forests where snowfall is no longer what it once was, the soil is releasing more carbon dioxide into the atmosphere instead of storing it. But reindeer can counteract this effect. If reindeer graze under trees, the soil will still capture carbon even if it doesn’t snow.

Christmas tree worms may help us protect corals

The Christmas tree worm looks like a Christmas tree, but it’s the kind of tree you see in Kodachrome photos of magazines from the 1950s. These tiny, cone-shaped, feathery worms in bright colors of blue, pink, fuchsia and orange attach themselves to coral reefs as larvae and then hang out motionless for the rest of their lives.

Although they are not particularly active, they are by no means lazy. Christmas tree worms have a symbiotic relationship with the coral they live on.

The tendril-waving adults circulate water around the coral, which helps the coral feed. Small polyps find shelter under the branches of Christmas trees, where they can hide from predators such as starfish. Because of this, scientists think we might be able to use Christmas tree worms 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 more Christmas tree worms. In the future, these worms may serve as an early warning signal, showing scientists where corals are stressed by ocean warming before conditions become dire.

Hanukkah armadillos are coming to your town

Back in 2000, when Friends’ Ross dressed up as an armadillo to teach his son the true meaning of Hanukkah, the real-life animal was still considered a creature of the Southwest. But things have changed.

First discovered in Texas in 1849, the nine-banded armadillo has expanded its range significantly, following a warming climate north and east of its historic homeland. A 2014 survey found that animals were able to establish themselves anywhere the average minimum temperature in January remained above 18 degrees Fahrenheit.

Turns out, that describes much of America. Take Iowa, for example. The state had no verified live armadillo reports until 2017. But through 2025, U.S. Geological Survey researchers documented more than 250 recent armadillo sightings in Iowa using public wildlife reporting apps, live trail cameras and other data sources.

Their data found hundreds of armadillos happily digging gardens as far north as Indiana and as far east as North Carolina. The data tells us what is good country for armadillos — warm but not too dry, with forest cover seems to be best — and where they are most likely to expand next — Ohio, Virginia and Michigan are all good candidates.

Narwhals survive in surprising ways

In 2007, a young researcher made a strange request to the director of Rosenborg Castle Museum in Denmark. She wanted to worm her way into the king’s throne.

The museum houses the Danish Coronation Chair, which was used by the real Danish kings from 1671 to 1840. But for Eva Gad, what makes it special is the spiraling narwhal tusks that adorn the sides of the throne. Gad’s research focuses on the history and future sustainability of the narwhal, an Arctic toothed whale beloved by young children and Buddy the Elf.

But narwhals, as a group, are not very genetically diverse—a fact that could be dangerous for them because it could limit their ability to adapt to a warming Arctic. Gad wondered what the narwhal’s ancestors were like. A DNA sample drilled from the 350-year-old throne is a perfect starting point. Perhaps if Mr. Narwhal can find his father like Buddy did, humans can better understand how to keep the species healthy into the future.

The museum allowed Gad to remove the sample from the throne and reassemble the entire thing. Since then, her team has learned a lot about these creatures. In fact, her research helped determine that narwhals have been living comfortably with low genetic diversity for thousands of years—which is somewhat surprising.

However, that doesn’t mean climate change doesn’t pose a threat to narwhals. Genetic data suggest that the species may currently be in a stable state with minimal diversity. If the Arctic gets hotter and temperatures drop further, narwhals could be in trouble.

The partridge was cut to death by a thousand cuts

Giving your true love a partridge in a pear tree might be an invitation to some simple target hunting. The red-legged partridge has been Europe’s most popular game bird for thousands of years. Its bones have even turned up in Paleolithic settlements.

But the red-legged partridge’s long association with humans has exposed it to a variety of negative impacts. It has been overhunted; flattened by tractors and other modern agricultural equipment; sickened and killed by the side effects of agricultural pesticides; deprived of care by former farmers abandoning the countryside for urban jobs; and outcompeted by other partridge breeds bred specifically for hunting.

Red-legged partridge populations may have declined by 40-45% between 2010 and 2020, according to the International Union for Conservation of Nature and Natural Resources, which determines whether a species is endangered.

Specifically, none of this has anything to do with climate change. But in the long term, all this makes partridges more vulnerable to the effects of climate change.

In 2021, a team led by Swedish and Italian scientists sequenced the red-legged partridge genome and learned some key information. First, the bird did poorly during the warming event 140,000 years ago. In fact, its population declined so much at that time that its genetic diversity has never recovered. Unlike narwhals, whose populations continue to grow and have low and stable genetic diversity, partridges have no such luck.

As a result, birds are not adapting well to climate change, their numbers have declined significantly and their ability to adapt is further reduced.

Carrying blessings on donkey’s back

Las Posadas are a Christmas tradition in Central and South America where the story of Mary and Joseph’s search for an inn is reenacted. Given their important role in the transportation of the Bible, donkeys are an important part of the celebration.

Research suggests donkeys may also play a role in helping humans 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 this in good times, but donkeys are particularly good at helping people survive climate disasters, a team of researchers at University College London wrote in a recent book on animal-human interactions under climate change. A donkey’s digestive system functions like an internal saddle bag – absorbing extra water when it’s available and retaining water when it’s scarce. Because of this, they are able to continue delivering water and food to humans even when other animals are unable to do so.

Donkeys also help support healthy ecosystems. Other herbivores can easily strip sensitive soil bare, leaving it vulnerable to erosion. But donkeys eat a wider variety of plants, so they are less likely to overgraze. A recent report by Tunisian researchers found that donkeys in the Mediterranean region prefer to eat invasive plants, which helps different species thrive.

Donkeys may even help protect us from insects and the diseases they carry. As the weather warms, the range of ticks and tick-borne diseases is expanding. But a new study from the University of Massachusetts Amherst has found that donkeys’ skin secretes a chemical that ticks avoid. When the chemical was applied to horses, ticks stopped biting them.

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