# Uakari

Uakari (UK: /wəˈkɑːri/, US: /wɑː-/) is the common name for the New World monkeys from the genus Cacajao. Both the English and scientific names are believed to have originated from indigenous languages.
A phylogeographic reconstruction identified a most recent common ancestor of living Uakari dating 1.7 million years ago, in the Solimões River, where the species was separated by the changing river and diversified.

## Geographic Distribution and Habitat

Uakari are native to South America, residing in the western portions of the Amazon Rainforest in Eastern Peru and Western Brazil. These animals were previously found in Colombia; however, they are though to be extinct as a result of excessive deforestation. It is a common belief that Uakari are specialized to live only in flooded regions of the forest. Research has shown that the majority of Uakari live in terra firme forest, which is situated at a much higher altitude than Uakari were previously thought to live in. The terra firme forest habitat resides 2000-2200 feet above sea level (600-700 meters above sea level), and therefore does not flood.

## Physical Description

The average Uakari weighs only 6-8 pounds (2.5-3.5 kg) and is around 1 1/2 - 2 feet long (40-50 cm). Uakari have unusually short, non-prehensile tails that are 5 inches (15 cm) long, causing them to rely on their arms, legs, fingers and toes to move through trees. With the exclusion of the tops of their heads and faces, Uakari's bodies are covered in long fur ranging in colors such as yellow/gold, orange, brown, or red depending on the species.

### Red Faces

A defining characteristic of Uakari are their hairless, red faces. This unique feature is not due to pigmentation in the skin, but rather a lack thereof. A lack of melanin, in combination with a thin epidermis and a high density of large capillaries in the face account for their scarlet complexion.
It is suspected that the intensity of redness is an Uakari's face can be an indicator of health, however this hypothesis has not been verified. The red faces are primarily used as a means of species identification, allowing members of troops (groups of Uakari) to differentiate between individuals. This feature also serves as a secondary sexual characteristic, where the intensity of redness is correlated with the level of testosterone in males and estrogen in females. In fact, levels of redness in a female Uakari's face varies throughout her menstrual cycle and can indicate when she is ovulating and most fertile.

## Behavior

Like most primates, Uakari are social creatures and live in groups called troops, ranging in size from roughly 10-30 individuals. Once they are able to reproduce, males will leave the troop in search of mates. Females reach sexual maturity around 3 years of age, and remain in the troop they were born into, reproducing about every other year. Uakari's breeding season spans from October to May and gestation last 6 months.

## Diet

Uakari forage in both the canopies and forest floor, where they primarily consume a large amount of unripe fruit for which they have specialized dentition. Uakari have strong jaws and fang-like teeth that allow them to bite through the hard exteriors of fruits and nuts. They also eat flowers, seeds, insects and leaves.

## Species

There are four species from the Genus Cacajao:
* Genus Cacajao
** Bald uakari or red uakari, C. calvus
*** Cacajao calvus calvus
*** Cacajao calvus ucayalii
*** Cacajao calvus rubicundus
*** Cacajao calvus novaesi
* Black-headed uakari species group
** Golden-backed or black-headed uakari, Cacajao melanocephalus
** Aracá uakari, Cacajao ayresi*
** Neblina uakari, Cacajao hosomi*
In 2014 Ferrari et al. proposed an alternative taxonomy for the C. melanocephalus group which recognizes the Aracá uakari as a subspecies of the golden-backed uakari, and also recognized Cacajao ouakary as a separate species, whereas current consensus is that C. ouakary is a junior synonym of C. melanocephalus. This revision is not universally accepted.