The Brown researchers tracked the changes in the dogs elbows and teeth over time, and according to Borja Figueirido, the lead author of the study, here’s why:
“The elbow is a really good proxy for what carnivores are doing with their forelimbs, which tells their entire locomotion repertoire,” Janis said.
The telltale change in those elbows has to do with the structure of the base where the humerus articulates with the forearm, changing from one where the front paws could swivel (palms can be inward or down) for grabbing and wrestling prey to one with an always downward-facing structure specialized for endurance running. Modern cats still rely on ambush rather than the chase (cheetahs are the exception) and have the forelimbs to match, Janis said, but canines signed up for lengthier pursuits.
In addition, the dogs’ teeth trended toward greater durability, Figueirido’s team found, consistent perhaps with the need to chow down on prey that had been rolled around in the grit of the savannah, rather than a damp, leafy forest floor.
Totally fascinating, isn’t it? Check out the article over on the Brown University website for the full story and additional background info.
Source: “Fossil study: Dogs evolved with climate change,” from https://news.brown.edu/articles/2015/08/dogs
Image Credit: Mauricio Anton