This is taking it back a fair way but I thought it was interesting to hear that mammals were originally nocturnal. Can we still attribute some of our nocturnal quirks to our distant past.
Mammals Literally Came Out Of The Dark Once The Dinos Were Gone
The first mammals emerged during the reign of the dinosaurs, adopting a nocturnal lifestyle to stay safe. It was only until the dinosaurs were wiped off the face of the planet that certain mammals began to assert themselves during the daylight hours, according to new research.
Both of the phylogenic timelines constructed by the researchers pointed to the same conclusion: mammals switched over into diurnal mode only after the dinosaurs were gone. The change was gradual, however, requiring millions of years of evolution; the "big switch" happened at some point between 52 to 33 million years ago (that's a big window, even for evolutionary biology).
"We were very surprised to find such close correlation between the disappearance of dinosaurs and the beginning of daytime activity in mammals, but we found the same result unanimously using... alternative analyses," explained lead author Roi Maor in a statement.