Thursday, June 28, 2018

Details on wolves and coyotes

We saw in the recent post that a statistic, the fixation index, that measures the genetic distance between two populations indicates that Europeans and sub-Saharan Africans are as far apart as wolves and coyotes.

This is a useful comparison because, while it is hard for humans to look at race without bias, who cares about wolves and coyotes?

I looked at Walker's Carnivores of the World to see what is says about these two species. Notice how I used the term species. Canis latrans (coyotes) and Canis lupus (gray wolves). The simple fact that blacks and whites are different as two (closely related) species is stunning. Coyotes and wolves interbreed, but biologists consider them separate species. But let's get specific.

First of all, the two species are obviously similar. Many of the major traits one would think of for one species is true for the other: carnivorous, keen sense of smell, cooperative hunting, etc. The two species live out their lives in very similar ways. So do blacks and whites.

But the two species are for from identical. Wolves are much larger: head and body length are 1,000 to 1,600 mm compared with coyotes at 750-1,000 mm. Wolves' tails are 350 to 560 mm, while those of coyotes are 300-400 mm. Coyotes have a narrower build, proportionally longer ears, and a much narrower snout. At birth, coyotes average 250 grams; for wolves, it's 450 grams. Coyotes appear to reach sexual maturity earlier than wolves, and their maximum longevity is 1.5 years shorter (14.5 vs. 16 years).

You might counter that perhaps they differ physically, but the real question is behavior, and the two behave the same. Not so. Wolves are more social. They run in significantly larger packs, they engage in cooperative hunting more often and on a larger scale, and they target much bigger game. While coyotes focus on rabbits and rodents, wolves don't focus on anything smaller than a beaver. They take down deer, moose, wapiti, caribou, bison, muskox, mountain sheep, etc.

Coyotes focus much more on scavenging. They are more likely to hunt alone or in pairs, and will even partner up with a badger. The coyote uses his superior nose to sniff out a rodent, while the badger uses his superior claws to dig up the meal they split. Coyotes can prey on sheep, but wolves also go after larger animals that are important to humans: cattle and reindeer.

The home range of wolves is much larger: the book reports a maximum of 13,000 sq km for wolves, but only 80 km for coyotes. Wolves need much more space: They can't get more dense than one wolf per 26 sq km while coyotes get as high as 2 per sq km.

You might counter again that behavioral differences in animals may be influenced by genes, but humans are controlled by culture. Over the years, I've read a number of studies on the heritability of animal behavior. It's often been of rodents--not known for their rich culture. I was stunned to learn that human conduct is influenced by genes just as much as that of animals. Heritabilities for animal behavior typically run from .2 to .4. Studies often give heritabilities for humans higher than that.

To see who we are more clearly, we have got to look at ourselves like we look at coyotes and wolves; as animals, plain and simple.

UPDATE: To clarify, I suspect that the environment is not as important for animal behavior as the heritability studies suggest. For both human and animal studies, anything not genetic gets thrown into the environment component, but it likely contains a lot of measurement error, random noise, and other factors that probably cannot be changed like the term "environment" suggests.

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