Anonymous said: Why do certain mammals have seasonal coats, while others (such as humans), do not?
Humans and our nearest ancestors evolved in areas of the world that don’t have particularly pronounced seasons. Animals that have seasonal coats tend to be making a go of it in places where temperatures and weather varies tremendously between summer and winter. At the equator, the average temperature shift between solstices at the equator is pretty much 0 degrees C, while in Alaska, the daily high shifts more than 30 degrees C over the course of the year. By the time humans were headed to more variable climates, we’d developed technologies like clothing that allowed us to survive in both the summer and winter but didn’t require millions of years of evolution to develop.