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Last updated at 17:46 BST, Tuesday, 10 July 2012

A dog's life

Summary

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'.

Reporter:

Victoria Gill

puppies, pa image

The transformation into 'hypercarnivores' has given dogs a reason to enjoy bones.

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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 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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Vocabulary

barren

land which does not have plants growing on it

landscapes

visible areas of land

big prey

large animals that are hunted by others

herd

group of animals that live together

skulls

bone cases for protecting the brain

species

group or type of animal or plant

evolved

developed gradually over time

descend

come from

overpowering

defeating through greater strength

genes

part of a cell which contains information about an animal's characteristics