Squirrels are not nocturnal for several reasons:
* Their food—nuts, seeds, and fruit—is easiest to find in daylight.
* Daylight lets them use sharp eyesight to spot predators.
* Their high energy needs are best met by daytime foraging.
* They are social and communicate more effectively by day.
* As homeotherms, they regulate body temperature well in warmer daytime conditions.
Some squirrels may be crepuscular, active at dawn and dusk, to avoid peak predator times.