Blurring the Lines

It is largely a Victorian myth that male gorillas would take a sexual interest in human females. Largely. No human has ever had to fear the sexual predation of (non-human) apes in the wild (dolphins, however, are a different story entirely). It is apparently rather a different story in captivity.

Reading Carl Sagan & Ann Druyan’s Shadow of Forgotten Ancestors, I ran across the following interesting passage:

“When raised among humans, they [Chimps] have been known to masturbate to pictures of naked people. (This is probably true only for those who, through prolonged contact, have come to consider themselves human. Wild chimps would no more masturbate to erotic images of humans than vice versa.)”

Now, if Sagan & Druyan have their information correct, this serves as a striking example of the dangers of observing animal behaviour in captivity.

Major pressure for behavioural change occur at boundary regions. This is one of the things that makes ecotones such a fascinating field of study. However, not all of these boundaries are terrain based. When two species are placed in close proximity, they tend to each adapt towards the presence of one another. The boundary between the species selects for adaptation. An excellent example of this is the Endler guppy experiments. Guppies placed in tanks with no risk of predation become brighter and more flamboyant to attract mates. Guppies placed in tanks with risk of predation become duller and more easily camouflage themselves in the substrate. In no way is either of these populations no longer a guppy, but the differences are striking. No animal exists in a vacuum. There is no eidos of any species. Take two populations of the same creature and put them in radically different circumstances, (if they don’t die) their behaviour and biology will begin to diverge (if this divergence continues long enough, speciation might occur). And the presence or absence of an entirely new species (a.k.a. the presence or absence of human observers) is one hell of a change in circumstance.

People like to draw a nice firm line between ourselves and the rest of Animalia, and it is just not merely wrong to do so, but actively misleading. It is fairly clear that people who interact with other animals in their daily lives are affected by the experience and they change their behaviour to match (entire myth structures have been built upon a human tribe’s native flora and fauna). So what does all this mean? Well…the practice of working with animals in any kind of setting where there is direct interaction between humans and animals is not of necessity accurate to the behaviour and condition of those animals in the wild. Your presence is going to cause an observer effect in them, and in all likelihood prolonged exposure will cause certain adaptive behaviours in you.

Of course, given that there is no eidos of a species is this such a bad thing? Not if you realise it. If you don’t, it can cause problems. We will look at a case study of this on Wednesday.

Sources & Further Reading

• Shadows of Forgotten Ancestors by Sagan & Druyan, 1992
• Finding a free full text of John A. Endler’s articles doesn’t look like it is going to work. Although it may be possible to get access to his work, and especially his 1980 Natural selection on color patterns in Poecilia reticulata through your libraries.