[entropicgravity]

Humans and dogs were two borderline species until dogs were domesticated. But together the two were so complementary, that they never looked back. The dogs had the speed, teeth, smell and baby sitting while humans had the weapons, rock throwing, intelligence and cooking. It was and is a killer combination that rose to the top of the animal world on earth so far.

[sema4hacker]

By baby sitting you mean dog hearing?

[entropicgravity]

It's tricky for women to raise children in the wild. Especially once kids get to the ages between 2.5 and 8 when they'll want to explore their ever changing environment but mom still has to look for plants and berries and keep an eye any dangers and carnivores that are around. Dogs protect their own little ones in the wild and readily help to keep an eye on the human youngsters in the same way. Further more dogs will sound the alarm when needed. It's one more helping, important hand, that dogs bring to the bargain.