Snakes! Good for your eyes.

A study out of the University of California, Davis reports that humans' and primates' superior close-up, color vision may have evolved in response to snakes. According to the authors "A snake is the only predator you really need to see close up. If it's a long way away it's not dangerous." I think saying "the only" is probably a bit of a stretch as it is the case of all ambush predators.

Other predators such as big cats, and hawks and eagles, evolved later. And then venomous snakes evolved about 60 million years ago, which forced primates to get better at detecting them.

"There's an evolutionary arms race between the predators and prey. Primates get better at spotting and avoiding snakes, so the snakes get better at concealment, or more venomous, and the primates respond," Isbell said.

And there are no dangerously venomous snakes on Madagascar, and lemurs, which only live on that large island and which have poor eyesight, have not evolved much in other ways in the past 60 million years, either, Isbell added.

The idea of the lemurs is somewhat convincing, but there are non-venomous Malagasy snakes (such as the one pictured above) capable of eating smaller lemurs, at least from a size standpoint. It would be interesting to compare eyesight in the more susceptible smaller lemurs in comparison to the larger, less likely to be snake prey lemurs to see if this piece of evidence holds up.

Thanks to reader Xian for the link