Mammals switched to daytime activity after dinosaurs died out, says study

Earliest mammals were nocturnal to avoid dinosaurs, which may be why there are relatively few modern daytime-active mammals, say researchers

The earliest mammals were night creatures which only emerged from the cover of darkness after the demise of the daytime-dominating dinosaurs, according to new research.

This would explain why relatively few mammals follow a daytime-active - or "diurnal"- lifestyle today, and why most that do still have eyes and ears more suitable for living by night.