Proboscis monkeys are renowned for their loud, bulbous calls and are among the most famous primates in the world. Contrary to popular belief, their noses are not so large that they need to be held under their arms when eating. They have a healthy diet.
Endemic to the Southeast Asian island of Borneo, these Old World monkeys are known for their social and friendly nature. They live in troops, with a harem group consisting of dominant males, females, and young males, while bachelor groups may include males and sometimes females.
These monkeys inhabit mangrove swamps and forests near rivers, where they feed on fruits, seeds, and leaves. They prefer unripe fruits due to the high sugar content in ripe fruits, which can cause their already plump bellies to swell further.
They are unique among primates for regurgitating and re-chewing their food (rumination) and have multiple-chambered stomachs similar to cows. The bacteria in their stomachs aid in digesting tough foods and detoxifying them.
Everything about these monkeys is large, from their stomachs accounting for a quarter of their body weight to their long limbs and tails. Males can weigh up to 24 kg (about 52 lbs) and have large noses, earning them the nickname “Orang Branda” or “Dutchman” from local Malays.
Read more:
It turns out that female proboscis monkeys prefer males with large noses, which can grow up to 17 cm (6.5 inches) in length. This trait is sexually selected, with women showing a preference for males with bigger noses due to its association with body quality and vocalization. The size of the nose indicates fertility and influences the male’s success in attracting females.
Interestingly, males with larger noses also tend to have smaller canine teeth, despite the lack of territorial aggression in proboscis monkeys. Troops of monkeys often interact, and members may move between groups, gathering at night to sleep in the same areas.
Proboscis monkeys are adept swimmers with partially webbed limbs, using a splash-free dog paddle to navigate their habitat. Their main threat comes from human activities like deforestation for timber and agriculture, leading to a drastic decline in their population.
Do you have a science question? To submit your question, email questions@sciencefocus.com or message us on our Facebook, ×, or Instagram page (remember to include your name and location).
Check out our ultimate fun facts and more amazing science pages.
Source: www.sciencefocus.com
