This subspecies of reindeer is only found on Norway’s Svalbard archipelago and stands at roughly five-feet long and three-feet tall - about half the size of other reindeer.
Svalbard reindeer - Rangifer tarandus platyrhynchus - "are actually quite morphologically unique from other reindeer. They’re shorter, they’re fatter, they’re hairier,” Samantha Paige Dwinnell, an ecologist who studies this unique, diminutive subspecies in Svalbard, tells Popular Science. “Their hair is twice as long and they are the fattest of the deer family in the world.”
Svalbard reindeer have been living on this remote northern archipelago for 5,000 years. Over that time, they have been isolated from other populations of reindeer on mainland Europe.
Most reindeer and caribou eat lichen - a hybrid of algae or cyanobacteria that grows on bark, wood, mosses, rock, soil and peat - but there "isn’t a whole lot of lichen available to them here,” says Dwinnell. “So Svalbard reindeer are a bit unique in their diet, in that they largely eat grasses.”
Like other reindeer and caribou, they have adaptations for their ever-shifting world. They technically live in what’s considered a high arctic desert where there is not a lot of deep snow, but it is still very cold. Summer temperatures typically only reach the mid-40s Fahrenheit. (32F equals zero Celsius).
“Their hooves can essentially be zero degrees Celsius, while their core body temperature stays stable,” explains Dwinnell.
The cell structure in their eyes also changes from the winter to the summer to allow them to see more of the low lights in the winter and deal with almost 24 hours of sunlight during the summer months.
Their legs are also shorter and closer to their body to prevent losing heat. As far as their added weight, it’s all about reproduction.
“With all reindeer and caribou, that’s [the fat] the currency they use for survival and reproduction,” says Dwinnell. “These animals manage to somehow be particularly fat, despite the low growing vegetation here. Basically they rely on those fat reserves to handle the long winters here.”
Their hair - twice as long as any other reindeer - also serves the same purpose.