Animals kill their own babies, gore rivals to death, and routinely commit incest. The difference between humans and animals is just a matter of degree.

In the aftermath of the gang rape in Delhi that horrified the nation and the world, Amitabh Bachchan tweeted “even an animal would not behave so”. While he was referring to the brutality of the attack, some readers asked if animals raped each other. Unhappily, I answered, some do. Rape occurs across the animal world from scorpionflies and garter snakes to ducks, geese, bottlenose dolphins, and primates. And humans.

Lest some readers assume anything that’s natural or occurs in Nature gives it sanctity, or draw the conclusion that behaviour is hard-wired in our genes, I’d like to set the record straight. Animals kill their own babies, gore rivals to death, and routinely commit incest. Although humans have been known to do all that, as members of a “civilised” society we don’t condone this behaviour.

But the difference between humans and animals is just a matter of degree.

Why do animals rape? Why did rape evolve at all? Unless we know what drives human behaviour, how do we deal with it? I’m limiting the definition of rape here to men forcibly committing a sexual act on women.

Among all creatures, we know of only a group of insects called scorpionflies that have a specific adaptation for rape. Males have an appendage called the notal clamp to pin females down. Even though they can rape, most male scorpionflies court females by offering a gift of food. But some discourteous males opt to use their clamps.

Ducks and geese are among the very few birds that rape. Most birds line up their cloacas, orifices for both excretion and reproduction, and males transfer sperm. But ducks and geese are unusual because they have an erectile penis.

Have penis, will rape?

There are often more drakes than ducks; when they pair off, a bunch of boy-ducks are left without mates. These guys gang up and jump on any duck that’s isolated from the flock. So what came first in ducks? Penis or rape? Being water birds, drakes have to make sure their sperm isn’t washed away. Could that be the reason the duck penis evolved? Or did it evolve to facilitate rape? I’ll save that knotty question for another day.

Among mammals, rape generally seems to occur in species where males are larger than females. They use their bigger size and greater strength to have their way. Male chimps are known to be violent. But contrary to assumptions, forced sex is infrequent. Only 0.2 per cent of copulations observed in the wild are coerced, says primatologist Caroline Tutin. Perhaps male chimps are on their best behaviour because they cannot attain higher social status without the support of females. Or, maybe the males bully the females so much generally that when the former solicit sex, the latter don’t refuse. Whatever the case, female chimps avert copulation with males they don’t like, say other primatologists.

Interestingly, bonobos, closely related to humans and chimps, show no signs of sexual aggression, or aggression of any sort. At territorial boundaries, where two rival troops would normally fight, bonobos have sex. Theirs is the most peaceful and explicitly sexual primate society known.

So our closest primate relatives, chimps and bonobos, are in a completely different league from us. According to behavioural ecologist Peter Kappeler and anthropologist Joan Silk, rape is “regularly observed” in only two primates: orangutans and humans.

There are two kinds of adult orangutan males: large dominant ones with well-developed cheek flanges and smaller guys without the facial pads. All the big studs have to do is stay put in their territories and howl loudly, and the females zero in on them; they are veritable chick magnets. The smaller chaps have nothing going for them; not only don’t they have the physique, they don’t have a territory to call their own. No orang female will give them the time of day. So instead of howling, these smaller chaps go prowling for sex.

(This is part one of a four-part series)

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