I was fascinated by this article about rats and racism. First, it examines an interesting issue of altruism. Second, it's about a series of studies in which the first results were disappointing, so people looked deeper and devised ways of testing different possibilities. Some of the best science involves digging down to core concepts like this, not accepting the first answer just because it meets somebody's expectation.
I love this comic about animal mating rituals from Humon Comics (which also has its own archive page). It shows terrific sexual diversity. I'll probably use some of these for F&SF races in the future. (I already have used some of these in the past; bonobos are a favorite.) Remember, if your speculative fiction isn't at least as weird as what we have on Earth, it's probably going to fall flat.