Sika deer can be active throughout the day but develop nocturnal tendencies in areas with heavy human populations. They have varied lifestyles, with some sika living alone and others in large same-sex groups. They gather in large groups in the autumn and winter and use over 10 individual sounds to communicate.

As herbivores, sika deer live on the local vegetation.

During the rut, or mating seasons, which peak from September through October, males become increasingly territorial and keep harems of females.

The sika deer inhabit woodland areas that are often lost to farms, making habitat loss a real threat. Hunting is also a threat, and some countries have domesticated sika deer for their antlers alone.

Native to East Asia and Japan.