13 avril 2017

L'évolution des chiens liée aux changements climatiques


Extrait du fascinant article:

A cooling, drying climate over the last 40 million years turned North America from a warm and wooded place into the drier, open plains we know today. A new study shows how dogs evolved in response to those changes, demonstrating that predators are sensitive to climate change because it alters the hunting opportunities in their habitat.

(...) The climate in North America’s heartland back around 40 million years ago was warm and wooded. Dogs are native to North America. The species of the time, fossils show, were small animals that would have looked more like mongooses than any dogs alive today and were well-adapted to that habitat. Their forelimbs were not specialized for running, retaining the flexibility to grapple with whatever meal unwittingly walked by.

But beginning just a few million years later, the global climate began cooling considerably and in North America the Rocky Mountains had reached a threshold of growth that made the continental interior much drier. The forests slowly gave way to open grasslands.

(...) At the same time that climate change was opening up the vegetation, dogs were evolving from ambushers to pursuit-pounce predators like modern coyotes or foxes — and ultimately to those dogged, follow-a-caribou-for-a-whole-day pursuers like wolves in the high latitudes.

(...) After all, it wasn’t advantageous to operate as a pursuit-and-pounce predator until there was room to run.



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