Амазонияның ақ мұрынды саки маймылы

Species of New World monkey

The white nosed saki (Chiropotes albinasus) is a species of bearded saki, a type of New World monkey, endemic to the south central Amazon rainforest in Brazil. Both its scientific and common name were caused by the authors working from dead specimens, where the skin on and around the nose fades to a whitish color. In living individuals, the nose is actually bright pink (though with fine barely visible white hairs). No other species of the genus Chiropotes have a brightly coloured nose. They are a primary consumer that eats seeds, fruit, flowers, bark, insects and leaves. They are also a social species that arrange themselves into large groups for many reasons such as sleeping, food gathering and travel arrangements. These social groups are important in situations where they are under attack by a predator as they decide on their anti predation strategies depending on the number of them available at the time. They are seasonal breeders, only reproducing in specific months during the year. In the 2020 IUCN Red List report, this species was listed as vulnerable with a decreasing population. They are dominant in the southern region of the Amazon since they share the eastern part with the Uta Hicks bearded saki which causes problems with food availability. They have also been observed towards the south western area of the Dos Marmelos River in Brazil.

As a primary consumer, the white nosed saki is dependent on habitats with enough food supply. Due to their similarity in diet with other Chiropotes, it is rare to find this species in habitats where they are required to coexist and compete over food supply. In fact, they live within this ecosystem because of their ability to easily organise groups for foraging to find their required food source. These upper canopies are where they have been observed spending most of their day to day lives.

The white nosed saki has three common physical features including a beard, two "tufts of hair" on its head, and a long "bushy" tail. fur body in contrast with their "reddish pinkish" noses and lips. Their teeth on the other hand are described as being of a "canine" appearance and these help them break through the tougher foods they eat e. g., fruits and seeds with harder outer shells. Then one of the more recent studies in 2009 identified the female weight to be roughly 2.56 kg with the male weighing in at 3.06 kg.

The white nosed saki are a diurnal species who engage in various activities during the day through the formation of groups which is their main system of socialisation. These groups have been found to consist of 19–30 individuals of both males and females. Although they group together and rely on each other for many of these reasons, they have very few means of communication with one another. for getting each other's attention generally, or during times of danger, but use more of a lower pitch during points where they are concentrated on a specific task such as relaxing or eating. In general, although they communicate in some ways with one another, they have been described as a shy species when it comes to social interaction and behaviour. Their largest known predator are birds of prey (e. g., the black hawk eagle). For this reason, they perform either "reactive" or "crypsis" related behaviours when they are under attack. Studies conducted in 2017 which observed many predation events across the Brazilian Amazonia discovered six common anti predation behaviours and strategies used by this species. The reactive ones included "mobbing, alarm calling" and "fleeing", while their crypsis behaviours involved "freezing, increasing of inter individual distance within a group, and hiding". From these behaviours, alarm calling, spreading out and hiding are those which most often occur after the attack. Spreading out has been claimed to be a "strong anti predator strategy" as it provides them with a clearer view over the existing predator and new potential threats, it increases their ability to hide better when they are alone, and it also allows them to continue communicating with each other over larger distances to confuse the predator. When it comes to hiding, in this study the species was observed in 7 out of 9 encounters dropping from their positions in the higher canopies to lower more "denser vegetation" where there are better chances for increased coverage. In cases where the vegetation is too dense and they cannot drop down, they will choose to move along the ground. They do this to lessen the amount of energy they use or waste on harmless situations. This need to constantly change their anti predation strategies has been identified as a common action for smaller primate species considering they are usually more at danger of being attacked than those that are larger in size. The pregnancy development phase, also known as the gestation period, has been studied to occur over a period of 5 months before reaching birth. With seeds, they are considered one of the more important foods in their diet since it is their "major protein source". One study described these seeds that they consume as being elastic and highly fibrous with [a] high crushing resistance". Although mainly eating fruits and plants, this species is not considered a very picky eater when it comes to these food categories as they have been found to eat a wide variety of over a hundred different plant types within the Brazilian Amazonia.

Under the 2020 IUCN Red List report, there have been a few key threats listed as the contributing factors to this species vulnerable status. These include environmental changes involving deforestation and habitat destruction due to human induced activities such as logging, agriculture, housing settlements, hunting and more.