There are about 300 species of monkeys on Earth, among which there are very strange creatures. For example, on the island of Kalimantan, also known as Borneo, there live proboscis monkeys. As you can understand from the name, the main feature of these primates is a huge nose, which sometimes hangs below the mouth. Moreover, this organ is huge only in males, in females it is much smaller. Because of this feature of appearance, proboscis monkeys are often included in lists of the ugliest animals in the world. But in fact, these are beautiful creatures, about which scientists are learning more and more interesting facts. For example, it recently became known why large noses grow in males. In addition, it was confirmed that their noses grow throughout their lives – in older monkeys they are huge.
Scientists have learned something interesting about proboscis monkeys. Photo source: dzen.ru
Photos of a proboscis monkey
Proboscis monkeys (Nasalis larvatus) are also known as kahau monkeys. They live only on the island of Kalimantan, and are not found in other parts of the world. They usually live in coastal areas, in dense jungles.
Male proboscis monkey. Image source: 7peremena.ru
Female proboscis monkey. Image source: goodfon.ru
These dog-sized creatures weigh up to 22 kilograms, with males being twice as heavy as females. They live in groups of 10 to 30 individuals, with only one male and many females. Occasionally, there are groups consisting of only males, but these gradually disintegrate as the monkeys find females and form new groups.
A group of proboscis monkeys. Photo source: fotovmire.ru
By size, proboscis monkeys can be compared to dogs. Photo source: pibig.info
Proboscis monkeys feed on leaves and fruits, and sometimes snack on flowers of plants. At night and in the morning, they rest in trees, so they go in search of food only in the afternoon or even in the evening. The main enemies of proboscis monkeys are crocodiles and leopards – the latter can easily catch even large males.
Male, female and baby proboscis monkey. Photo source: ornella.club
New Discovery About the Cahow Monkey
The scientific journal Scientific Reports recently published the results of a study in which scientists discovered why males of this species of monkey need such big noses.
Australian scientists studied the nasal cavity inside the skulls of monkeys. To do this, they scanned the skulls stored in museum collections. They were most interested in the size and shape of the cavities, as well as how they could affect the sounds made by males. The results of the study showed that the larger the noses of primates, the louder and deeper the roar they make.
For Proboscis Monkeys, Size Matters! Photo Credit: popsci.com
According to the authors of the scientific work, the ability to produce a loud roar thanks to its large nasal cavity allows males to show who is the boss. It is also an indicator of good health and good physical fitness – this is very important for attracting the attention of females.
The more females there are to mate with, the more likely the males are to produce more offspring. A larger nose, which can more easily produce a loud roar, may help males demonstrate their qualities and status to potential mates, the scientists explained.
The researchers also noted that the noses of the kahau monkeys help them find each other in the dense jungle. They live among the trees, so they often cannot see the members of their group. By making a loud roar, the proboscis monkeys quickly let everyone know where they are.
Proboscis monkeys live in coastal mangroves and forests, so they often cannot see each other through the trees. The ability to scream loudly is important for communication with each other, especially among males, said anthropologist Catherine Balolia.
When roaring, males straighten their noses. It is possible that females find large noses attractive: for them, it is as beautiful a feature in appearance as straight teeth and an upright posture are for us.
Read also: How scientists tried to turn a monkey into a human
The nose of a proboscis monkey
Scientists also found that males' noses get bigger with age. This suggests that older proboscis monkeys always have more authority than younger ones.
You agree that proboscis monkeys are wonderful creatures, right? Photo source: otobase.co
Finally, it is worth noting that the Soviet biologist Igor Akimushkin already in the 20th century assumed that the large noses of kahau monkeys are needed to produce louder sounds. It turns out that Australian scientists have confirmed the scientist's version.
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Proboscis monkeys do not stand out for their highly developed intelligence, but they surprise with their appearance and behavior. But orangutans have recently amazed scientists with their ability to treat themselves with medicine. It has been noted that they treat wounds by applying leaves of medicinal plants to them, and these “plasters” help very well.