Daily Activities of Proboscis Monkey (Nasalis larvatus) in Curiak Island, Banjarmasin, South Kalimantan

This study aimed to determine the natural daily activity of proboscis monkeys in the Curiak Island, Banjarmasin, South Kalimantan. The observed behaviors include 1) rest, 2) eat,
3) groom, 4) agonistic, 5) vocalize, 6) play, and 7) movement. The observation method used was one of the Altmann method, named instantaneous scan sampling, each individual is observed with a short duration of 30-60 seconds followed by other individuals. The observation was divided into two times, morning and day, each time had 4,5 hours observed duration. The results showed highest activity of proboscis monkeys recorded during the six-day observation was
resting, and the lowest was agonistic. The activity of proboscis monkeys was strongly influenced by the availability of food, protected trees, and threats on Curiak Island.