North American bull caribou (Photo provided — National Park Service)

I recall years ago two young boys having a conversation: “There’s no such thing as Santa Claus,” the older boy insisted. But the younger boy wasn’t buying it.

Come Christmas Eve, he was going to stay up all night, just to catch a glimpse of old Santa and his legendary sleigh full of presents. What excited the little guy the most, though, was the thought of seeing those remarkable flying reindeer on the roof!

“Santa’s reindeer really can fly, can’t they?” he asked me, catching me completely off guard. I hesitated, then told him that reindeer were deer, very much like the whitetails we see around here but with thicker bodies, shorter legs and broader hooves. I added that whitetails and reindeer are cousins. And that moose and elk are reindeer cousins, too. Fortunately, he let it go at that.

In North America, reindeer is the name given to domesticated or semi-domesticated varieties of caribou; caribou being the French-Canadian name for wild reindeer. In Europe, all caribou are called reindeer.

Scientists have always been somewhat specific about the differences between the two, noting that domesticated reindeer tend to be shorter, smaller, and lighter in color than wild caribou. They note too, that wild caribou herds migrate with the changing seasons, usually allowing vegetation in grazing areas to regrow, whereas domesticated or semi-domesticated reindeer more-profoundly impact feeding grounds and need to be driven to better grazing areas when food becomes scarce.

Interestingly, a recent genetic mapping, published in Nature Climate Change, asserts that Eurasian reindeer and North American caribou are, in fact, different but closely related animals. Cousins. Their genetic signature suggests that during the last ice age, North American caribou and Eurasian reindeer became separated, developing into two different breeds. It wasn’t until the ice melted that populations again had the chance to interbreed. As such, the study also reveals something about the role that climate change has had on their ongoing evolution.

To most people, however, reindeer and caribou are one and the same, Rangifer tarandus, a native to the Arctic tundra and adjacent boreal forests. Their original range included northern Maine and parts of Minnesota. Small herds, numbering less than two or three dozen animals, may still exist in the Rocky Mountain regions of Montana, Wyoming, Idaho and Washington state. They are the only species in nature, deer or otherwise, in which both sexes grow antlers. A bull’s antlers can grow to 4 feet in width and weigh more than 30 pounds. Antler length in females is usually only 9 to 20 inches. All males drop their antlers in winter. Pregnant females usually retain their antlers until after birthing.

In the spring, each pregnant cow gives birth to a single calf. At birth, calves weigh between 10 and 20 pounds. Within an hour of their birth, they can walk. Within a day, they can outrun even the fastest humans.

In the wild, caribou reach sexual maturity in 29 to 41 months. Mating occurs in late September and October, during migration, when herds are traveling from summer to winter feeding grounds.

During the summer, caribou herds find an abundance of grasses, sedges, browse and low-lying vegetation on which to feed. In winter, when food becomes scarce, they’re able to lower their metabolic rate and reduce their food intake. Their large, concave hooves allow them to dig easily through blankets of soft snow, to eat lichens and other available ground-vegetation.

But the Arctic is warming, with precipitation more often occurring as “rain-on-snow” events, which cover vast areas of Arctic “pasture” with a thick layer of dense, hard ice, frozen firmly to the ground, leaving the food source beneath it inaccessible. In 2013, a “rain-on-snow” event resulted in the starvation and freezing deaths of 61,000 reindeer in the Yamal Peninsula of northwestern Siberia, Russia. A similar event in 2006 killed 20,000.

As with other animals bred for agricultural purposes, different reindeer varieties have been developed to meet different human needs (i.e. milk and milk products, meat, pack and saddle animals) and environmental conditions. Some have been selectively bred for many generations while other attempts at domestication simply didn’t work. Some domestic herds have escaped back into the wild only to become — well, not-quite-wild herds. Occasionally, individual domesticated animals wander off with passing migrating herds, never to be seen again.

With all the breeding, crossbreeding and genetic manipulation that has taken place, you would think that anything can happen. Nonetheless, I’m unaware of any variety of reindeer that can fly.

Please don’t tell the children.