Yes, Virginia, there is a Santa Claus. But if we're not careful, his reindeer could soon be nothing more than a myth.

Climate change has put quite a toll on Santa's herd over the last 40 years. Populations of one North American reindeer subspecies, the Peary caribou (Rangifer tarandus pearyi), have dropped nearly 85 percent since the late 1960s—from 50,000 to fewer than 7,800 today, according to the International Fund for Animal Welfare (IFAW).

Another reindeer subspecies, the barren-ground caribou (pdf) (R. t. groenlandicus), is much healthier. But problems growing from a warming environment that are faced by all reindeer are well illustrated by a genetically distinct population of the subspecies known as the Dolphin–Union caribou (Rangifer tarandus groenlandicus x pearyi). Each year, the Dolphin–Union herd crosses the frozen Dolphin and Union Strait in Nunavut, Canada, to get to Victoria Island, where the animals spend their summers. If the 160-kilometer-wide strait does not develop ice that is thick enough, the reindeer can fall through it and drown. This can, and does, happen to all reindeer species when they try to cross rivers where the ice is too thin.

Climate change also affects reindeer's ability to gather food: Warmer temperatures actually create more land-based ice in their habitat as rain falls on top of snow and then freezes to form a hard shell that prevents the animals from digging through to find ground vegetation.

IFAW has previously petitioned the U.S. Fish & Wildlife Service to protect these two species under the U.S. Endangered Species Act (ESA). The Service was legally required to respond to that petition by December 14—a deadline that it has not met.

Why list Canadian reindeer under the ESA? According to an IFAW statement, such a listing would serve the two species symbolically: "Listing the species under the Endangered Species Act will not only bring international awareness to the plight of these species..., heightening and hopefully acting as a catalyst for global action to save them from extinction," it would also create some practical trade restrictions, as live reindeer or their parts would not be importable into the U.S.

"It is clear that these two subspecies of reindeer are in need of help right now," Jeff Flocken, IFAW's Washington, D.C., office director, said in a prepared statement. "The U.S. Fish & Wildlife Service needs improved listing systems and adequate resources to ensure that both domestic endangered species and foreign imperiled species such as these reindeer are evaluated in a timely manner."

Image: the Barren-ground caribou, via Wikipedia