The Science of Aliens, Part 3: Have They Overcome Their Savage Past, or Might They Want to Eat Us?

Reviewing our own species’ behavior suggests a cautious approach to contact with extraterrestrials.

Lions do it. Humans do it. What about extraterrestrials?

Social structure is enormously important in trying to predict how alien societies might behave, as discussed in Part 1 of this series. It determines whether a society’s actions will be dominated by cooperation or selfishness. And the range of possible behaviors is enormous, from altruism—individuals helping others at a cost to themselves, even if it means increasing the other’s chances of survival and reproduction—to cannibalism, where an individual increases its own chances of survival by consuming another individual of its own species as food.

The latter extreme, cannibalism, has recently been studied by a group led by Mike Boots from the University of California-Berkeley. The researchers used Indian moth larvae in their experiments and found that less selfish behavior evolved under living conditions that forced individuals to interact more frequently with siblings. It’s true that Nature allows for cannibalism under extreme circumstances, where some individuals are sacrificed so that the species can survive. But as the research by Boots shows, individuals are more reluctant to employ this extreme practice if they have more interactions with each other, such as sibling interactions.

Reluctant or not, we shouldn’t be too hard in judging the moth larvae, because cannibalism has now been documented in more than 1,000 different species, including humans. There have been cannibalistic human tribes in the past, and even today there are cases of cannibalistic behavior in individuals. Neanderthals, our closest hominid species, are believed to have practiced cannibalism. More disturbingly, in certain societies cannibalism has been used for ritual purposes. An especially shocking example is the Aztecs, who are believed to have used razor-sharp obsidian blades to slice open the chests of their victims and rip out their hearts, as a prelude to ritual cannibalism.

Of course, cannibalism isn’t humankind’s only bad behavior—there are plenty of other examples. In an unforgettable two-part episode of Star Trek: The Next Generation (“All Good Things”) humanity is put on trial by the Q continuum. The critical question: whether our species has evolved beyond its savage past.

Of course, other species on our planet have no qualms about such matters. Think about lions, where a new male taking over the pride kills the cubs of his predecessor. We might debate whether it’s ethical to kill individuals of one’s own species for food in extreme circumstances, but Nature doesn’t seem to have a problem with it if it’s advantageous for the survival of the species. (Nature does not seem to care about the individual at all, sorry).

I think the same biological laws would apply to aliens as well. A spacefaring extraterrestrial civilization would be expected to reside at the top of their food chain. The more technologically advanced they are, and the more power they have over their fellow species, the more damage they can do (compare a Stone Age axe with today’s nuclear bomb). That should make us cautious if and when we make contact with an advanced alien species. We won’t know ahead of time whether they have overcome a savage past. Humans certainly have not.

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