Mammals

A new study paints a grave future for the killer whale, all because of the now-banned chemicals polychlopinated biphenyls — PCBs.

By Kristen Hall-Geisler

It's a natural phenomenon known as a 'squirrel king.' But what's the deal and why do squirrels get tangled up?

By Jamie Allen

A dolphin named Billie learned a dolphin-show trick from some captive dolphins, taught her wild friends how to do it and started a fad.

By Jesslyn Shields

The Indian giant squirrel is covered in flamboyant colors like orange, black and bright purple. But why?

By Jamie Allen

It used to be assumed that African bush elephants avoided the sound of an angry bee hive. Now researchers believe they have receptors to detect a bee's alarm pheromones.

By Jesslyn Shields

The Humboldt marten was thought to be extinct until it was rediscovered in 1996. Now it is threatened again.

By Jesslyn Shields

Breaking news: Dolphins and porpoises don't actually look very much alike.

By Jesslyn Shields

Once a week or so, sloths climb down from their trees and poop on the ground. It feels so good, they do a little dance. But this time of pleasure is also a time of peril.

By Alia Hoyt

Once you accept squirrels aren't going anywhere, you can apply a more creative approach to keeping the critters away from your prized tomatoes.

By Jamie Allen

Think your bed is cleaner than a chimp's? Researchers at North Carolina State University set out to find the answer.

By Kristen Hall-Geisler

Koala populations in Australia are in decline, in part due to the ravages of chlamydia, a sexually transmitted bacterial infection.

By Carrie Tatro

It pays to be brainy when you're a ring-tailed lemur.

By Jesslyn Shields

The platypus may look a bit absurd and bizarre, but its milk might hold the secret to fighting antibiotic-resistant bacteria.

By Jesslyn Shields

Nutria are jumbo-sized rodents that reproduce and eat at a jumbo-sized pace.

By Jesslyn Shields

Urban coyotes have a fierce and formidable reputation as midnight predators, but coexistence with humans is possible.

By Carrie Tatro

Some people mistakenly believe that if chimps are socialized from an early age, they're not a threat to humans. But these five families found out the hard way that chimps will always be chimps.

By Nathan Chandler

Why do squirrels exhibit behavior that can get them killed by cars? And how can you avoid them?

By Jamie Allen

The first new rat species found in the Solomon Islands in 80 years has been uncovered. But due to deforestation of its habitat, very few may still exist.

By Jesslyn Shields

Fall is in full swing and that means squirrels are busy hoarding nuts for winter. So how do they remember where they buried them? Research suggests they use mnemonic strategies.

By Jamie Allen

Due to a quirk in their anatomy, injured hedgehogs can experience skin inflating to the size of a basketball, which can be a painful and life-threatening development.

By Laurie L. Dove

Thanks to the excesses of narcoterrorist Pablo Escobar, Colombian waterways now house a population of these invasive African giants.

By Jesslyn Shields

Sure, these mammals may be cute and cuddly. But that doesn't mean their bite can't pack a punch.

By Kate Kershner

By frightening top predators, the fear of humans may be distorting ecosystem processes even more than previously imagined.

By Jesslyn Shields

A new scientific study reveals that the smells unique to meerkat communities aren't produced by the meerkats themselves.

By Chris Opfer

A new genetic analysis clarifies the evolutionary relationships between five modern and extinct elephant species.

By Jesslyn Shields