You might only know dire wolves from the TV series Game of Thrones, but they were real dogs that grew up to six feet long in order to hunt the megafauna of North America tens of thousands of years ago. Quite a few of their remains were preserved in the La Brea tar pits. Dire wolves were identified as a species in the 1850s, but now DNA analysis tells us more about them. For example, they weren’t really wolves.
After sequencing five genomes from dire wolf fossils between 50,000 and 13,000 years old, the researchers found that the animals belonged to a much older lineage of dogs. Dire wolves, it now appeared, had evolved in the Americas and had no close kinship with the gray wolves from Eurasia; the last time gray wolves and dire wolves shared a common ancestor was about 5.7 million years ago. The strong resemblance between the two, the researchers say, is a case of convergent evolution, whereby different species develop similar adaptations—or even appearances—thanks to a similar way of life. Sometimes such convergence is only rough, such as both birds and bats evolving wings despite their differing anatomy. In the case of dire and gray wolves, lives of chasing large herbivores to catch some meat on the hoof resulted in two different canid lineages independently producing wolflike forms.
The DNA study is causing scientists to rethink how and why dire wolves went extinct, and how they should be classified. Read more about dire wolves at Scientific American. -via Metafilter
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