All I can really say is that animals usually keep a closer "society" then humans do. When they make that leap as a species to work together, they are incredibly dependent on others. They would most likely adopt a policy of helping each other, "ill watch your kid, then you watch mine." It was obviously more primal than that, but since it worked, these animal societies grew and became more common and effective than independent living.
My God & I are one & the same,
We have the same face we have the same name.