Untitled Document Diurnal, Nocturnal, Cathemeral Activity Patters Diurnal primates are active during the day. The benefits include better visual foraging and visual communication. However, diurnal primates face increased predation, possible heat stress, and competition for food from birds and other primates.
Nocturnal primates are primarly active at night.
They are better protected from predators and have fewer competitors for food. Nocturnal primates tend to utilize vocal communication during hours of darkness when sound travels better due to humid night air. Many primates are actually active throughout a twenty-four hour period on a sporadic basis. This type of activity pattern means these primates sleep periodically throughout the day.