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A dog's life

Summary

10 July 2012

Scientists who have traced the ancestry¹ of the domestic dog say they've worked out why man's best friend loves to chew bones. Researchers from the national university of Colombia found that dogs' jaws² and teeth started to grow larger about 8 million years ago, when the animals first started hunting in groups. This gradual transformation³ is what turned our favourite pets into what the scientists called 'hypercarnivores'.

Reporter:

Victoria Gill

Report

Eight million years ago, a shift in the climate caused more barren, open landscapes to spread across the globe. And without the cover of trees, large animals grouped together for protection. 

This, the scientists say, was when wild dogs started to work together, teaming up to drive big prey⁴ out of the herd⁵. The Colombian team examined the skulls⁶ of more than 300 dog species, building a timeline that revealed how their jaws and teeth had evolved. 

This revealed that the wolves from which our domestic dogs descend⁷ started to change when they began to hunt in packs. From then on, the dogs with the biggest teeth and most powerful jaws were most likely to succeed in overpowering their prey, so they passed their 'hypercarnivorous' genes⁸ on to the next generation. 

The researchers say that this is what's given our pet dogs such good evolutionary⁹ reasons to really enjoy chewing on bones.