Sumatran rhinoceroses (Dicerorhinus sumatrensis) are mainly recognized as animals that are active during the twilight hours, meaning they are most active at dawn and dusk. However, their activity patterns can differ depending on factors such as their surroundings, the availability of food, and disturbances caused by humans. Although they are not strictly active at night, they may display some behaviors typically associated with nocturnal animals, such as being active during the nighttime in specific situations. Sumatran rhinoceroses are generally acknowledged as solitary and secretive creatures, and their nighttime or twilight behavior aids them in navigating their dense forest habitats with limited interference from humans.