While the wooly musk ox may like it cold, fruit flies definitely do not. They like it hot, or at least warm. In fact, their preferred optimum temperature is very similar to that of humans—76 degrees F.
Scientists have known that a type of brain cell circuit helps regulate a variety of innate and learned behavior in animals, including their temperature preferences. What has been a mystery is whether or not this behavior stems from a specific set of neurons (brain cells) or overlapping sets.