Advances in organ and computer models are raising the prospect that some animal experiments could be eliminated. But there ...

What purpose does the penis serve? Why is it that members of one species have no penis at all, while those of another have two? Why do they vary so much in shape and size? And where do vaginas, or the ...

Do animals feel love, anger, or empathy? Researchers have long dismissed such ideas as anthropomorphism, arguing that attributing human emotions to animals was unscientific.

Marine animals, such as the extremely simple flatworm Trichoplax, are ideal model organisms for studying the early evolutionary origins of animal life processes. Despite measuring only a few ...