Newswise — Just one night each year, nine tiny magic reindeer pull Santa and his toy-filled sleigh around the world. They are Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner, Blitzen and Rudolph, and it's said that these mythical animals are the only reindeer that can fly. There is surely something magical at work when 36 hoofs and one glowing red nose can help Santa deliver his toys to girls and boys around the world in just one night.
But what about the reindeer who are not part of the nine-member 'deer dream team'? The ones who move each day throughout the Alaskan and Canadian tundra, rather than the North Pole, and who live among caribou rather than elves? Though they do not possess the magic of Santa's reindeer, they are an interesting breed nonetheless.
Dr. Perry Barboza is a physiologist at the Institute of Arctic Biology, University of Alaska at Fairbanks, who studies reindeer and their closest cousins, caribou. Barboza explains that some of the characteristics of the Alaskan and Canadian reindeer get overlooked in the Christmas crush.
He points to the fact that male reindeer shed their thick antlers at the end of mating season in early December. The females also have antlers, but their thinner version stays with them throughout the winter. Does this mean that Rudolph and the team are all females?
"It appears that way," says Barboza. who also says that while Rudolph's nose has a very shiny glow, the noses of all other reindeer are furry, and usually white and gray, the colors of their snout.
At the start of winter, females may be as much as 50% body fat "seals on hooves," as Barboza likes to describe them. The fat, which can be a couple of inches thick on their rumps, insulates them from months of cold -- as low as minus 45Â° F. The fat also provides a source of energy that the body draws on at a time when reindeer must subsist mainly on lichen, a combination of fungus and algae.
Barboza offers other interesting facts about reindeer:
"¢ Reindeer eat plants and herbs. The drying tundra resulting from climate change is leading to the loss of lichen ranges, which may adversely affect reindeer herds.
"¢ Reindeer have bigger fat stores than caribou going into the winter, but both groups are about the same body weight at the end of winter, when they've used their stores.
"¢ Males go into winter with much lower fat stores than females, as low as 5%, because they use so much energy during the fall mating season. So, losing the weight of their antlers is probably an energy saver.
"¢ Bulls have a shorter lifespan. They live about six years, while females live 8-9 years. Their shorter lifespan is attributed to the greater energy they expend during mating season, to injuries that occur as they compete with other bulls for mates and to their hormones, which suppress the immune system and leave them vulnerable to even minor infections.
"¢ Reindeer have specially designed coats with hollow hairs that help maintain body heat.
"¢ Their circulatory systems are designed to keep the cooler blood in the reindeer's limbs from drawing warmth from the warm blood in their core body.
"¢ The fatty acids in their legs become more unsaturated closer to the hoof, which helps prevent the membranes from freezing.
Want to Watch the Magic Reindeers on Christmas Eve?
If you want to watch the mythical reindeer fly with Santa on Christmas Eve, simply log on to the US government's North American Aerospace Defense Command's (NORAD) website at http://www.noradsanta.org/en/tracksanta.htm. They have been tracking Santa and that "nose so bright" for more than 50 years.
Editor's Notes: An audio version of this story will appear on Life Lines, the podcast of The American Physiological Society. You can find it at http://www.lifelines.tv.
Physiology is the study of how molecules, cells, tissues and organs function to create health or disease. The American Physiological Society (APS) has been an integral part of this scientific discovery process since it was established in 1887.