It is a mainly nocturnal species which can be attracted to light by night.

The eyes are large, as this fish is mainly nocturnal.

The black slug is mainly nocturnal and avoids exposure to sunlight.

Although mainly nocturnal, they are sometimes active at dawn and dusk.

Kangaroos are mainly nocturnal and a collision with one can be fatal.

Like other solifuges, they are mainly nocturnal and found in arid habitats.

They are mainly nocturnal, but some have been seen basking in the early morning or late afternoon.

This species is mainly nocturnal, but may also be crepuscular.

These fish are mainly nocturnal, but will also emerge from their hiding places during the day, after some time getting accustomed to the aquarium.