Did you know that having large genitals can actually cause extinction? Inverse science editor Yasmin Tayag explains how a species ran into evolutionary disaster after becoming too big for their britches.

Scientists from the Smithsonian Museum of Natural History studied 6000 specimens from 93 different species of ostracods (near-microscopic, clam-like crustaceans) that lived 85 to 65 million years ago.

Throughout the 20-million-year span in which the scientists studied, some species of ostracods lived the whole time, while others only lived a few thousand years. That may sound like a while, but to give you some perspective, modern homo sapiens have been around for over 300,000 years. So what was the common factor that tied the short-lived species together? Big genitals. The scientists found that in species where males had larger genitals, the extinction rate was 10 times higher than that of the species with smaller, um, appendages. Sorry, guys, as it turns out size is everything.

The team of scientists believes these little guys were putting all of their evolutionary energy into having killer crustacean sex that they were ignoring every other aspect of survival. Similarly to a hot ‘n’ heavy casual hookup, it’s really fun in the moment, but if you don’t put the work in for a long-term relationship, it’s not going to last.

So it turns out small and steady wins the race. And if you want to find out what 65 million years have done to these guys and their junk, let Yasmin tell you all about it. Spoiler: It’s crazy.