Something killed a lot of sperm whales in the past—and it wasn’t whalers

Sperm whales are a genetic puzzle. The deep-diving, squid-eating giants that inspired Moby Dick are found in every ocean, where they can mate with partners from around the world; as such, they should be quite genetically diverse. Yet, their genetic diversity is actually very low, hinting that something killed a lot of them off in the past. And that something wasn’t whalers.
Read more: http://www.sciencemag.org/news/2018/05/something-killed-lot-sperm-whales-past-and-it-wasn-t-whalers?source=Snapzu