What Happened to the Boys? In Fossilization, That Is #fossil #nature #unexpected

[image error]This is a weird discovery. In museum fossils of ancient megafauna, males outnumber females by at least two to one. Assuming ancient mammals are pretty much like mammals today, the ratio at birth should be close to 50/50, so why do paleontologists dig up more boys than girls?

Bison, mammoths, bears. Museums hold more male bones than female (something determined by measuring bones and sometimes by sampling DNA)

They found the same bias in all but a few mammalian orders, with bats, sloths, and anteaters among the exceptions. atlasobscura.com

No one set out to study sex discrepancies in fossil collections, but there it is. One hypothesis suggests that males are driven out of herds or forced to hunt over a larger area than females, end up dying in a wider variety of places, and that would favor preservation. But, since 100% of mammals die, it’s still kinda weird.

Thanks to the Swedish Museum of Natural History paper in Current Biology and to a study in Proceedings of the National Academy of Sciences.