Others live in colonies of up to 20 million. The vampire bat hunkers down in a cluster of 200 or so, yet each mother is able to find her own child when she returns at night from a lengthy flight, despite the fact that her son or daughter is hidden like a lost toddler on an overcrowded beach. To top it off, if an unrelated neighbor has had slim pickings in its search for blood, a returning mother will disgorge some of her stomach contents to the needy. On a future night the bat who was aided when she was down on her luck will make her way through the bewildering mob to pay back her benefactress by offering her fresh food if she, too, has been starved by snarls of fortune. A cerebral cortex of substantial size makes it possible to pinpoint patrons and trade favors as if in a commodities exchange.
Elephant groups are also highly interlaced.
Each troop focuses upon a female elder, relying on her strength and wisdom. Her cerebral cortex is enormous, holding lessons learned 40 years ago and shuttling them down the line to generations newly born. To knock our homo chauvinism down a peg further, even language is not totally unique to us. Robert Seyfarth and Dorothy Cheney have shown that though monkeys don't gush a steady stream of nouns, verbs and sentences, they do erupt with symbolic sounds which act as words. Most famous are the vervets, whose distinctive chutters and whirs warn of killer birds circling the skies, lethal snakes slithering on the ground, and leopards stalking at eyeball height.