The University of Chicago Press reported Perry Barboza's study, published online by the Physiological and Biochemical Zoology journal, argues the animals pulling Santa through the air on his Christmas Eve round trip across the globe are caribou rather than the traditionally accepted reindeer.
"Although the mechanisms of flight for Santa and his team are as yet unknown, the energy required by his team of animals to fly around the world from pole to pole is considerable," the study reads. "The animals that draw the sleigh must deliver high power with a minimal flight mass. Such a level of energy expenditure in a ruminant capable of flight would require significant food intake, because larger fat stores increase flight mass. Calves entering their first winter have the greatest power-to-mass ratios, because their legs are proportionately longer and their body is leaner than those of adults. Although Siberian reindeer may appear a suitable choice, North American caribou are leaner and longer-legged than reindeer during this time of year. Caribou can also better sustain very high food intakes -- of a diet including dry lichens and formulated rations -- at 6 percent of body mass per day. What has been reported in sightings as "eight tiny reindeer" are therefore likely to be young caribou."