Squirrels are those weird little creatures that run around and steal bread or whatever food they can lay their little paws on. Something that piqued my curiosity when watching a group of squirrels on campus recently, is how jerky or rapid and sudden their movements tend to be. They are not like humans who move relatively smoothly, or elephants who lumber along, or even whales which move gracefully through the water. Instead, squirrels move when they want very quickly before just stopping for no apparent reason. The jerky movements could be because the muscle actions on the scale of the squirrel is so much quicker and stronger. Think about it – the properties of the muscle (such as underlying mechanism for motion and relative strength of one cell or even a group of cells) in the squirrel is probably quite similar to us humans. However, because the mass they need to move and the distance to move is significantly smaller, their movement ends up ends up being quick and sudden, like the tremors you see when manipulating something under a microscope.
I noticed when watching the same group of squirrels, that they tend to be very skittish, stopping whatever they were doing just so that they can listen for things. It would make sense as in general, the deader the squirrel, the fewer babies it can make to spread its genes. Such a survival mechanism - being very alert to its surrounding and prepared to run away very quickly -would greatly benefit squirrels as it would help them live longer and thus spread its genes further.
Their fur seems to be not very long, but warm enough to allow them to not freeze to death in the winter time. What I wonder though is why they have such bushy tails. It is not as if they have a large quantity of blood there. Maybe the thing it might help with is with balance, having the extra weight of the fur to help counterbalance the squirrel while climbing trees or running around. It might also act passive stability when jumping. The fur could act like the feathers on a shuttlecock, helping the squirrel fly straight when jumping. If this is actually true, I don’t know. This is just speculation on my part, and given the scale of the squirrel, these aerodynamic effects might not do anything.