Mad About Science: Evolutionary Behavior

By Brenden Bobby
Reader Columnist

In the grand scheme of things, we’re all basically just apes with awesome tools. Just about all of our daily rituals, from brushing our teeth to how we act at work, originate from a time when our ancestors called the African jungles home.

Before we continue, it’s important to note the typical dismissive response used by those who don’t understand evolution:”You really believe we came from chimpanzees?” No, I don’t. The fossil record shows that humans and chimpanzees share a common ancestor. Chimpanzees aren’t our great grandparents, they’re more like our funny cousin who bears a greater resemblance to grandma and grandpa than to us.

The most evident and complicated remnant of our evolutionary past is our social structure. While evolution has given us an edge at working as huge, collaborative societies, many of our social behaviors echo great ape behavior as far up as the offices of presidents, dictators and kings. Most primate behavior is fairly isolated and territorial, where encroaching groups whip one community into a violent frenzy and create a war over local resources and land. Chimpanzees seem to be an exception, having been observed coming together peacefully and even swapping mates — a behavior expressed in a surprising number of American suburbs.

A common practice among many great apes is polygyny, or one male collecting a harem of females. What’s interesting is that the male picks one and sometimes two females he decides to rear children with, instead of trying to sire as many babies as possible. This might sound weird and alien, but it’s been accepted in several cultures around the world, from some Native American tribes to conservative societies in the Middle East. It’s also a close mirror to how a cheating spouse acts.

Another very common form of primate social grouping is multimale-multifemale. Social hierarchy is very important in these kinds of groups, where dominant members of both sexes are chosen to rule essentially as aristocrats. The lower members must defer to the respected group leaders before taking a variety of actions or they feel the wrath of the group. If you’re smirking and saying, “That sounds like high school,” you’re right. It’s an exact replication of a primate’s multimale-multifemale hierarchy. Unlike apes, we only need to endure this social organization for a few years. After that, most of our brains tend to grow past the primal surge of hormonal development to a more stable, rational form.

Laughter may be another trait we inherited from our primate ancestors — luckily for me, or I wouldn’t get to write this article every week. Expressions of joy are a rare thing in the animal kingdom and laughter is even rarer. We have observed chimpanzees, orangutans and other great apes making a sound similar to human laughter when tickled. Dogs have even been observed making a specialized panting noise when they’re excited, which seems to achieve the intent of laughter: expressing joy. This behavior in domesticated dogs is likely a form of mimicry to impress humans, as when Husky dogs “talk.” In primates, it’s a genuine expression.

Emotional expression, language skills and the use of tools are the reasons that humans have been able to create a global civilization. Yet, all of these traits are directly linked to our primate ancestors, starting with language. Several types of apes have been seen shaking their head “no” to dissuade others from performing a foolish act. Though one might assume it’s just the flailing motion of a wild animal, it has been witnessed in this context time and time again, particularly with mothers trying to educate their infants. Many apes have also been observed naturally conveying things like landmarks or directions with repeated hand signing, which may indicate that sign language preceded verbal language in humans by a considerable span of time.

One of the more curious ancestral holdovers of primate behavior is social grooming, particularly among human females. Getting your hair done or going to the salon for a manicure/pedicure, is closely tied to social grooming in great apes. It’s a form of social care, in which members of a group can bond with one another while elevating their social status, either within that group or another. Japanese macaques are famous for performing this ritual in the volcanic hot springs of Japan.

Before I get called out for being sexist here, it’s safe to say that men share some primordial ape behaviors, too. Have you ever been at a bar and witnessed two guys about to get into a fight and noticed the way they push up against each other and start barking insults within an inch of each other’s faces? This behavior is often seen in apes that are trying to challenge another they perceive as a threat to their social status without having to come to blows. It’s in our instinctual behaviors to preserve our health, but also to challenge authority to better our position in life. That’s right: You can thank early hominids for aggressive Dudebros.

There are a lot of other interesting behaviors I was hoping to include, but it appears I’ve run out of space. If you’re curious about what other cool stuff we’ve inherited from our ancestors, you should stop by the library and ask the first person you see with a lanyard where you can find books on monkeys and apes. Just don’t fling your waste while you’re there.