Humans' treatment of other animals shaped our evolution

Humans are one of the few animals that adopts and cares for other animals. Our cross-species connections might be older and more important than we ever imagined, driving human evolution for millions of years and even helping us invent language.

Even before the formal domestication of animals thousands of years ago, humans formed strong bonds with animals that have no obvious counterpart elsewhere in the animal kingdom. According to biological anthropologist Pat Shipman, this interdependency between humans and animals actually stretches back two and a half million years, and figuring out why our ancient ancestors created these links can help us better understand our overall evolution.

As Shipman explains, deciding to care for another animal is a seemingly irrational decision, particularly for hunter-gatherers millions of years ago:

No other mammal routinely adopts other species in the wild — no gazelles take in baby cheetahs, no mountain lions raise baby deer. Every mouthful you feed to another species is one that your own children do not eat. On the face of it, caring for another species is maladaptive, so why do we humans do this?

She believes the answer is found by looking at another singular human innovation, stone tools. These tools, first invented 2.6 million years ago, turned humans into fearsome predators and radically shifted their place in the ecosystem. Humans to deal with this shift by observing the behaviors of potential competitors and potential prey, and the best way to do this was to bring animals permanently into their lives. Those who knew more about animals were more likely to survive in the new paradigm, and this evolutionary advantage explains why humans now form these connections with animals throughout the entire world.

Shipman has an even more radical proposal - the huge amount of data gathered through the observation of animals created a need for storing and communicating this information, which gave rise to language itself. As indirect evidence of this, she points towards the earliest cave paintings:

"Though we cannot discover the earliest use of language itself, we can learn something from the earliest prehistoric art with unambiguous content. Nearly all of these artworks depict animals. Other potentially vital topics – edible plants, water, tools or weapons, or relationships among humans — are rarely if ever shown."

This longterm observation of animals eventually transformed into domestication. Indeed, her theories provide an answer for a question about the domestication of dogs that's so basic that most wouldn't even realize it's worth asking:

"Why would you take a ferocious animal like a wolf, bring it into your family and home, and think this was advantageous? Wolves eat so much meat themselves that raising them for food would be a losing proposition."

It's an excellent question, and yet dogs were domesticated thousands of years before any other animal. She thinks the answer is that these first dogs weren't seen as pets but instead as living tools that allowed humans to harness all the behaviors they had observed for millions of years and use it for their own purposes:

"As living tools, different domestic animals offer immense renewable resources for tasks such as tracking game, destroying rodents, protecting kin and goods, providing wool for warmth, moving humans and goods over long distances, and providing milk to human infants."

If Shipman's theories are correct, then the human ability to observe and interact with animals is directly responsible for the success of tools and the creation of language, and without this animal connection we wouldn't be the species we are today. You know, I'm starting to feel very inadequate that I've never had a pet.

[Current Anthropology]