Sustainable Footprint

Wolf hybrides are winners

When the wolf had been extrirpated from most of the USA his smaller relative took her chance. The coyote took over the role of toppredator. But for that one needs some wolf blood.

Not many animal species have been hunted as fanatically as wolfs. In Europe the wolf was symbol of everything evil. When colonists came to America they took their hatred of wolves with them. By the beginning of the 20th century the species was extinct in the United States (except Alaska). Only one clever wolf managed to suvive until 1921. ("He was the master criminal of the animal world"... said the report)

In recent years wolfs have been re-introduced in some areas, not very successfully, but now is is again allowed to hunt wolfs.
A few wolfs in reservations are tolerated, but not more. The wolf is still the great absentee in the ecosystems of the US

And that is good luck for a predator of an other species, the prairywolf or coyote. The coyote is much smaller. During the last 90 years coyotes have moved far outside the prairies, where they used to hunt small animals. Today coyotes live in the eastern forests of the US and even in southern parts of Canada. They manage to catch even deer, and often they are bigger than the coyotes of the prairie. They have adapted to the new situation all by themselves, or did they use a tric?

Skulls of coyote (left) and wolf

Coyote

They did, according to Roland Kays, Abigail Curtis en Jeremy Kirchman in Biology Letters (september 2009) .The eastern coyotes are not exactly ‘pure’. The scientists studied the mitochondrial DNA (m-DNA) of 776 animals. M-DNA is inherted only from mothers. They also studied and compared the skulls of 686 coyotes.

They found that the coyotes in Ohio derive directly from the real prairie coyotes like the ones living in Texas and Nebraska. The genetic deversity is only much smaller: they have 11 different types of mDNA, the other ones in the prairie have 22. The conclusion is that they derive from a small group of migrating animals. They are real coyotes.

In the forests in the northeast of the US the genetic diversity is even less: only 3 versions of mDNA. One of these is the same as in Ohio. And - surprise, surprise! - one of the other is not even from coyotes, but from a subspecies of wolfs living in Canada.

It is clear what has happened: coyotes have migrated to the region north of the Great Lakes and mixed with wolves. The resulting hybrids have moved to the eastern forests of the US. These animals have an bigger and broader skull and a lot stronger jaw muscles than their relatives from the prairies. They show also greater sexual dimorphism.

Thus, hybridization is a conduit by which genetic variation from an extirpated species has been reintroduced into northeastern USA, enabling northeastern coyotes to occupy a portion of the niche left vacant by wolves.

This is a case of extremely fast evolution, thanks to hybridising. The slightly wolfy version of the coyote is more successful than the original, probably because he can kill bigger prey. It is also more successful than the real wolf, probably because people do not look at it as the devil in a furcoat – so they do not shoot immediately when meeting one…

Source: Biology Letters

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