Experts have recently revealed fossil evidence that indicates that the earliest of mammal ancestors may have started out as nocturnal creatures, meaning daytime hunting and foraging may have been a trait that evolved in later species. Experts have long-known that you can determine when a mammal was active by looking at its eyes.
Small and brow-shielded eyes are meant to see through the glare of a midday sun, but massive wide-eyed peepers are intended to catch as much light as possible for nocturnal shenanigans. According to a study recently published in the journal Proceeding of the Royal Society B, 300-million-year-old synapsids – the reptile-like mammals that modern mammals are thought to have evolved from – all boasted a bony ring that surrounded their eyes.
This ring apparently allows experts to see the exact eye size of extinct synapsids, something nearly impossible to tell in later mammalian fossils. Observing this, researchers Lars Schmitz, William Myron Keck and Kenneth Angielczyk at the Field Museum of Natural History then theorized that when mammals arose from synapsids 100 million years later, they likely inherited those nocturnal ways. While somewhat of a shot in the dark, the researchers do explain that this could change what experts think about mammalian evolution.