Apr 19 2011

Efficient Slaughter

Humans are efficient killers – and we have been for a long time. It seems like the inevitable consequence of our cognitive evolution combined with our tribal and hunting instincts. It’s one of those quirks of evolution. When the right combination of features arises in a species, it can have profound effects on an entire ecosystem – or an entire planet.

But let’s back up a bit to pre-historic Homo sapiens. Various hunter cultures figured out ways to mass slaughter hundreds or even thousands of animals, even very large animals. In the Americas, for example. the Clovis culture (11-13k BP) learned how to take down very large prey, such as mammoths, but they generally killed only one or a few at a time.

They were succeeded by the Folsom culture (9-11k BP) who figured out how to surround their prey and kill dozens at a time. Later paleo-indians figured out how to herd bison over cliffs, killing hundreds at a time. It is still controversial the extent to which this overkilling contributed to the decline and extinction of some large game in the Americas (vs environmental or other factors).

Another example of mass slaughter, and the subject of a recent discovery, is found in Syria. Structures known as “kites” because of their appearance from the air are comprised of stone walls in a funnel shape leading into a walled pen. Archaeologists believe these structures were used to guide large herds of migrating animals, like gazelles, into the pens, where they were slaughtered by the hundreds.

Researchers have recently discovered a “killing pen” near one of these kites, with thousands of gazelle parts and signs of human butchery. There are equal numbers of males and females, and several yearlings – it looks like an random sampling of an entire breeding population. This provides the first direct evidence that the kite structures were indeed used to funnel herds to be captured and slaughtered.

Again – it is not known what impact this practice had on gazelle populations, but it must have been significant. It is also unclear if this practice was purely performed to obtain a source of meat, or if there was also a ritual aspect to it.

These examples remind us that humans are a very clever and deadly species. Even with what we would consider very primitive weapons (such as the stone points of the Paleo-Indians), a little bit of ingenuity led to the slaughter of entire herds.

Now, of course, that human cleverness is combined with more advanced technology (which itself is the result of that cleverness). I am all in favor of efficiency and technology, but we do have to recognize the downside of this given human nature. We have driven many species to extinction through over hunting. (Although most species that have gone extinct at the hands of humans resulted from loss of habitat or simply importing rats, cats, and dogs into new ecosystems.)

The efficiency of hunting of even some ancient humans reminds me of a short story in which scientists were running evolutionary simulations in a futuristic supercomputer. They noticed that whenever the big cats crossed a certain threshold of intelligence, they would wipe out the ecosystem through overhunting. They simply became too good at hunting.

The bigger concept here is that evolution is a blind force. Populations and species are adapted to their local conditions, without any long term planning. So if it just happens to come about that one species hits upon a combination of abilities and survival strategies that can potentially threaten the entire ecosystem – so be it. Some argue that this has already happened with humans. Hopefully we can employ our cleverness to do what evolution cannot do – plan for the future.

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