It’s the End of the Male As We Know Him (And Boas Feel Fine)

If the end of men is upon us, as asserted by a summer cover story in The Atlantic, you can add boa constrictors to the list of those sticking their tongues out at males as they slide to irrelevance.

Boa constrictor females, it turns out, don’t need males to get involved in the birthing process.

Warren Booth, a postdoctoral researcher in entomology who keeps and breeds snakes, studied the case of a strange momma snake that gave birth to two different litters of all-female babies – all with the mother’s rare color mutation – and found no evidence of male involvement in any of the 22 “virgin” births. That’s despite the fact that the mom had plenty of opportunities to mate with males – males were present and courted her before she gave birth to the rare babies. Stranger still, this same mom had babies “the old-fashioned way” a few years before her miraculous pregnancies.

Booth’s study of the first documented case of asexual reproduction in boa constrictors, published this month in Biology Letters, upends conventional wisdom on reptile reproduction.

Snake sex chromosomes are a bit different from those in mammals – male snakes’ cells have two Z chromosomes, while female snakes’ cells have a Z and a W chromosome. Yet all the female babies produced by this super mom had WW chromosomes, a phenomenon Booth says had not been seen before in nature and was thought to be impossible. Only through complex manipulation in lab settings could such WW females be produced – and even then only in fish and amphibians, Booth says.

Booth calls the ability to reproduce both ways “an evolutionary get-out-of-jail-free card,” and suggests that maybe asexual reproduction among reptiles is more common than scientists think.

Booth now keeps one of the miracle babies. He’ll attempt to breed her when she reaches sexual maturity. Will she mate with a male, have babies on her own, or – like her mother – do both?

In any case, because of her WW chromosomes, any baby she has will be female.

Maybe the reports of male demise are greatly exaggerated. Or maybe my 8-year-old daughter is right: “Girls rule, boys drool.”