Why Are Marine Mammals Losing Their Hair?
In 2013, while studying Guadalupe fur seals on San Benito Island in the Mexican state of Baja California, Fernando Elorriaga-Verplancken spotted something unusual. Through his binoculars he saw that some of the animals had bright yellow patches on their bodies, ranging from a few square inches in size to more than half of their otherwise gray-ish coats. “What is that?” wondered Elorriaga-Verplancken, a seal ecologist at Mexico’s National Polytechnic Institute.
When he and his colleagues got closer, they saw what was wrong. The seals had lost some of their guard hair—an outer layer of coarse, long fur that lends fur seals their coloration—revealing their yellow undercoat.
Sporadic hair loss is rare in any mammal and especially worrisome in fur seals. They have relatively little blubber, and to stay warm in cool waters, they rely on air trapped between the layers of their guard hairs and undercoat. Any gap in that insulation will waste precious energy, weakening the animals and making it harder for them to hunt, mate, care for their young, and survive.
Elorriaga-Verplancken has now seen afflicted seals on the island
