The Real Dire Wolf Ran Into an Evolutionary Dead End

The Real Dire Wolf Ran Into an Evolutionary Dead End

The dire wolf, an animal many people know from its fictional incarnation in “Game of Thrones” was a heavy-boned, powerful predator that roamed North America up to about 11,000 years ago, or perhaps even later, preying on large animals like extinct horses, bison, sloths and even mammoths.

While it was nowhere near as big as its television version, the dire wolf was about 20 percent larger on average than the gray wolf, and it was long considered a sister species, Canis dirus rather than Canis lupus.

But an international team of scientists reported Wednesday in the journal Nature that the first sequencing of the dire wolf genome showed an unexpectedly large genetic separation between the two species, big enough that the dire wolf is not just a separate species but a separate genus. They resurrected an old name, Aenocyon, for the genus, first suggested in 1918 by John Merriam, a paleontologist, but soon discarded. The dire wolf is the sole species in the genus.

The last common ancestor of the gray wolf and the dire wolf was about 5.7 million years ago, the researchers reported. And another surprise was that the dire wolf didn’t seem to interbreed with other species — as dogs, wolves, coyotes and other canids do. In evolutionary terms, it met a lonely end.

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