How Scary are Humans?

New study shows African savanna animals fear humans more than lions

“In a video posted by Western University biologist Liana Zanette, who led the study, several types of animals from elephants to warthogs can be seen reacting to human voices and making a quick escape.”

“Another video shows the elephants' reactions to hearing lions, which seems to lead to a more confrontational reaction, with the elephants aggressively approaching and attacking the broadcasting speakers. “

Well Doh!

Suppose you were walking down the street and heard two humans talking behind you; you would keep walking. Nothing unusual here.

Suppose you were walking down the street and heard two humans talking in Spanish behind you; would you keep walking, or might you turn around to help the tourists?

Suppose that you are a warthog and hear the roar of a lion? Evolution has equipped you with a brain that can evaluate not only the raw meaning of the lion’s roar (I am hungry, I am satiated), but the distance of the lion (fifty yards, a hundred yards, a half a mile away).

As a warthog your brain would tell you to be worried. Or nit.

Now suppose you were a warthog and heard a sound that was not a lion or an elephant; not a gazelle of a tree falling in the forest. Suppose that as a warthog you heard a strange sound, a sound that you had never heard before.

Would you flee?

Absolutely. Evolution has prepared your brain to recognize all the sounds that your successful ancestors experienced, and has equipped you to evaluate the safety level of each known sounds.

But Uncle Henry discussing their investments with Aunt Griselda? Never heard that before! Would you give it the Okay, or would you scamper off to a safe hiding-place?

Evolution favors potential ancestors who scamper away (“escape”) than potential ancestors who shrug and say “That sound has not previously done me any harm”.

Here I am questioning the logic behind the summary report published in the press, and also the study in “Current Biology”

The scientific contention that the simpler explanation is more likely to be the correct one suggests that it is not “fear of human voice” that triggers fleeing as much as “fear of unknown sound”

As for the study itself, the text is populated with probabilities and numbers, but is very light on logic behind the arguments and values.

Nineteen species were tested and shown to react (“escape”) from human voices.

Think of those herds of zebra and wildebeests in their thousands, grazing across the Rift Valley floor. Not many humans in those scenes. I suggest that human presence in Kruger National Park has been always very rare, despite the number of Jeep-powered safaris. Until the past two hundred years, the only human predation would have been pedestrian spear-wielding warriors; a threat to warthogs, but not a very strong one in terms of numbers. Certainly not enough to impact a herd of zebra.

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