“In sober truth,” wrote the British philosopher John Stuart Mill, “nearly all the things which men are hanged or imprisoned for doing to one another, are nature’s everyday performances.” While it is true that rape, torture and murder are more commonplace in the animal kingdom than they are in human civilization, our fellow creatures almost always seem to have some kind of evolutionary justification for their actions — one that we Homo sapiens lack.
Cats, for instance, are known to toy with small birds and rodents before finally killing them. Although it is easy to conclude that this makes the popular pet a born sadist, some zoologists have proposed that exhausting prey is the safest way of catching them. Similarly, it’s tempting to describe the way African lions and bottlenose dolphins –– large, social mammals –– commit infanticide (the killing of young offspring), as possibly psychopathic. Interestingly, experts suspect that these creatures are in fact doing themselves a favor; by killing offspring, adult males are making their female partners available to mate again.
