Seventy-five million years ago, mammals couldn’t compare to the big boy reptiles ruling the earth. Still, that didn’t stop one spunky, prehistoric squirrel-like creature. He wasn’t hungry for meat, but he needed his minerals. He eyed a dino bone, the equivalent of modern-day vitamin shop, and wrapped his teeth around it, his very own corn-on-the-cob-osaurus.
Yesterday, researchers published a paper in Palentology on these exploits. They claim to have found the oldest known mammal bite marks.
The researchers found the bones bites in two Canadian, Late Cretaceous-period dinosaur bone collections–and also on additional bones during fieldwork in Alberta. They suspect the marks were made by multituberculates, extinct rodent-like creatures, and they first found them on the femur bone of Champsosaurus, a swamp-dweller that looked a bit like an crocodile.
The researchers say that the form of the bite marks indicate that they were made by opposing pairs of teeth, a tell-tale sign of mammal chompers (think rats). And the fact that they came from paired upper and lower incisors points to multituberculates. Though these early mammals didn’t have the bite power that modern day rodents developed, their marks look similar.
Nicholas Longrich, lead author on the paper, says in a Yale press release:
“The marks stood out for me because I remember seeing the gnaw marks on the antlers of a deer my father brought home when I was young,” he said. “So when I saw it in the fossils, it was something I paid attention to.”
Related content:
Discoblog: Egad! Oldest Spider Web Dates Back to Dinosaur Era
Discoblog: Will Jurassic Park Ever Really Come True?
80beats: New Analysis Reveals Color of Dinosaur Feathers for the First Time
80beats: The Ur-Sneaker: 5500-Year-Old Shoe Found in Armenian Cave
Image: Nicholas Longrich/Yale University
In my latest column for Discover, I take a look at 
Two years ago I noted that 
“This research explored differences in how men and women approach “friends with benefits” (FWB) relationships. Specifically, this study examined sex differences in reasons for beginning such involvements, commitment to the friendship versus sexual aspects of the relationship, and partners’ anticipated hopes for the future. To do so, an Internet sample of individuals currently involved in FWB relationships was recruited. Results indicated many overall similarities in terms of how the sexes approach FWB relationships, but several important differences emerged. For example, sex was a more common motivation for men to begin such relationships, whereas emotional connection was a more common motivation for women. In addition, men were more likely to hope that the relationship stays the same over time, whereas women expressed more desire for change into either a full-fledged romance or a basic friendship. Unexpectedly, both men and women were more committed to the friendship than to the sexual aspect of the relationship. Although some additional similarities appeared, the findings were largely consistent with the notion that traditional gender role expectations and the sexual double standard may influence how men and women approach FWB relationships.”
