As a ‘bat fan’, I looked at the following headline with interest…
Seems that the hopeless romantics over at ScienceDaily.com have gotten into the spring spirit!
“There must be something in the warm breeze. A study on bats suggests that bats produce twice as many female babies as male ones in years when spring comes early. The earlier in the spring the births occur, the more likely the females are to survive and then reproduce a year later, as one-year olds, compared to later-born pups, according to Robert Barclay’s research published in PLoS ONE.”
(The Big Brown Bat, Eptesicus fuscus )
“The early-born females are able to reproduce as one year olds, whereas male pups can’t,” explains Barclay, professor in the Department of Biological Sciences. “Thus, natural selection has favoured internal mechanisms that result in a skewed sex ratio because mothers that produce a daughter leave more offspring in the next generation than mothers who produce a son.” Barclay analyzed long-term data on the variation in offspring sex-ratio of the big brown bat, Eptesicus fuscus, a common North-American species that consumes insects.
“In this species, more eggs are fertilized than eventually result in babies, so there is some mechanism by which a female embryo is preferentially kept and male embryos are resorbed early in pregnancy,” says Barclay. But, he adds, the biochemistry behind the skewed sex ratio is unknown. In other words, female bats can choose to give birth to female baby bats… we just don’t know how they’re going it!
Well… a girl has to have SOME secrets!
 Brown bats have the ability to select the sex of their offspring, as they produce more female offspring in early springs. (Credit: Photo by Ken Bendiksen)
 Credit: Photo by Bull Snook.