Squirrel

Squirrels are small rodents that are mentioned in How to Train Your Dragon (Franchise).

Description
There are multiple rodents that can be classified as squirrels, including tree squirrels, ground squirrels, flying squirrels, chipmunks, marmots and prairie dogs.

Typical squirrels usually have slender bodies with bushy tails and large eyes. The hind legs are longer than the fore legs with four or five toes. They have an unique ability to rotate their ankles 180 degrees. By doing so, they can climb a tree downwards.

Function
While there is no function for the squirrels in the franchise, in reality some species can be kept as pets.

Dragons: Riders of Berk
In the episode The Terrible Twos, when Fishlegs sees a baby Typhoomerang, he thinks that he saw a flaming squirrel or a flaming chipmunk, unknowing it was a dragon.

"Fishlegs: And something weird jumped out of the bushes. It was like a... flaming squirrel. Hiccup: Really? A flaming squirrel? Fishlegs: Or a chipmunk. Or some other flammable rodent."

- Fishlegs describing what he saw