Why the Fossil Record Is Mostly Male

 From Atlas Obscura:

They found 75 percent of bison fossils in such collections were males. This wasn’t a surprise, based on what Pečnerová had theorized about mammoth herd behavior, since bison social structure similarly isolates young males. “By [the mammoth] anology, some of the male bison are going off and doing stupid things,” Gower says, adding that the researchers were not able to test for age to further support the theory, but he hopes to in the future.

Among the brown bear populations, two thirds were male, and this was a little more surprising. Bears don’t herd. “In America, you might observe a group of brown bears in Yellowstone congregating around a garbage bin, but they’re usually on their own,” Gower says. They would have to consider other behavioral differences that might explain the discrepancy. The researchers theorize that males had much larger ranges than females, so they died across a wider area and range of environments, which in turn made their fossils more easily discoverable by humans. The sex discrepancy thinned out for specimens collected at higher altitude, where food is more scarce and females subsequently have larger ranges. Pečnerová says she was surprised by these findings, as bear populations tell a very different story than do mammoths and steppe bison. “However, if you give it more thought,” she says, “it makes perfect sense.” (Read more.)

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