10 July 2012
Scientists who have traced the ancestry 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' jaws and teeth started to grow larger about 8 million years ago, when the animals first started hunting in groups. This gradual transformation is what turned our favourite pets into what the scientists called 'hypercarnivores'.
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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 prey out of the herd. The Colombian team examined the skulls 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 descend 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' genes on to the next generation.
The researchers say that this is what's given our pet dogs such good evolutionary reasons to really enjoy chewing on bones.
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land which does not have plants growing on it
visible areas of land
- big prey
large animals that are hunted by others
group of animals that live together
bone cases for protecting the brain
group or type of animal or plant
developed gradually over time
defeating through greater strength
part of a cell which contains information about an animal's characteristics