Hairless Animals—The Naked Truth

Think you’re having a bad hair day? At least you’re not a penguin chick in the South Atlantic.

Large numbers of baby penguins in South Africa and Argentina are mysteriously losing their plumage, the Wildlife Conservation Society announced recently. (See penguin pictures.)

These so-called “naked penguins” are victims of a rare disease called feather-loss disorder. So far, the possible causes include pathogens, thyroid disorders, nutrient imbalances, or genetics, according to the conservation group.

Scientists who recently studied the disorder in Argentina’s Magellanic penguins found that bare chicks grew more slowly and were smaller in size and weight than their normal feathered kin.

A “naked” Magellanic penguin chick in Punta Tombo, Argentina.

Photograph courtesy Jeffrey Smith

Naked penguins got me thinking about how nature has evolved ways to keep us warm and dry. Hair is a defining feature of mammals, as feathers are to birds. Hair can also serve as camouflage—think a leopard’s spots—or as defense mechanisms, like a porcupine’s quills, which are actually modified hairs.

Sometimes, though, species are just born “naked.”

Take us, for example. Oddly, humans are unique among primates for our near-total bodily hairlessness. In fact, only a handful of the 5,000 or so mammals—mostly semi-aquatic species such as whales, walruses, and hippopotamuses—are not covered in dense fur, National Geographic News reported in 2003. (Human hairlessness may be a strategy to shed the ticks, lice, fleas, and other parasites that nestle deep in fur.) Of course, we wear clothes for warmth—and for other reasons that don’t need elaboration.

Then there’s the naked mole rat, a type of burrowing rodent with wrinkly skin and a generally walrus-like appearance. Like insects, several dozen rats live together in colonies led by one dominant rat—the queen. The hairless critter was also the subject of a successful April Fool’s Day prank in Florida in 1984.


A naked mole rat was the subject of a 1984 April Fool’s Day prank.

Photograph by Robert Clark, National Geographic

The Transylvanian naked neck chicken has a featherless, bright red neck that’s the result of a random genetic mutation, I reported last month. Why the bare neck? It’s not to give Romanian vampires easier access—more likely, it helps the birds handle the heat better, scientists say.

Sightings of hairless creatures are also fodder for urban legends, like the mythical chupacabras.

Tales of a mysterious monster that sucks the blood of livestock have exploded in Mexico, the U.S. Southwest, and even China since the mid-1990s, when the chupacabra was first reported in Puerto Rico (map), we reported in 2010.

“In almost all these cases, the monsters have turned out to be coyotes suffering from very severe cases of mange, a painful, potentially fatal skin disease that can cause the animals’ hair to fall out and skin to shrivel, among other symptoms,” the story said.

Mange can also affect other species in the wild—in 2003 in Florida, people reported seeing balding bears. (Read the hair-raising tale of Dolores, a bear that went bald at a German zoo.)

Likewise, red foxes with a rare genetic condition known as Sampson—an abnormality in which the animal lacks a layer of fur called guard hair—have been sighted throughout the country in recent years. These diseased animals have a kangaroo-shaped head, big upright ears, and a long ratlike tail.

Not exactly what you’d call a, er, foxy look.

Check out more weird coverage on National Geographic News.

Wildlife

Christine Dell'Amore, environment writer/editor for National Geographic News, has reported from six continents, including Antarctica. She has also written for Smithsonian magazine and the Washington Post. Christine holds a masters degree in journalism with a specialty in environmental reporting from the University of Colorado at Boulder. Her book, South Pole, was published in 2012.