Mammals
Bald Uakari
Cacajao calvus · also called red uakari
Perched in the flooded canopy of the western Amazon, a bald uakari displays a face so vividly red it doubles as an honest signal of good health, a short-tailed monkey whose seasonal habitat rises and falls with the river beneath it.
Overview
The bald uakari, Cacajao calvus, is a distinctively red-faced monkey native to rainforest and wetland habitat across parts of the western Amazon basin. Its vivid bald red face functioning as a genuine health signal, unusually short tail for a New World monkey, and close dependence on seasonally flooded forest make it one of the more visually striking and ecologically specialised primates found anywhere in the Amazon.
A face that can’t fake good health
Unlike species that can mask poor condition, the bald uakari’s bare red face makes health status difficult to hide, its colour fading visibly with illness in a way that gives potential mates an unusually honest signal to judge by.
Status
Vulnerable, having declined due to hunting and the loss of seasonally flooded rainforest habitat across parts of the western Amazon basin.
Bald Uakari: common questions
Why does the bald uakari have a red face?
This species has a distinctive bald, bright red face, a colouring closely linked to good health, since illness or parasitic infection can cause the skin to fade to a paler, duller shade, making face colour a visible signal of physical condition to other individuals.
Why is the bald uakari's short tail unusual?
This species has a notably short tail relative to its body, an unusual trait among New World monkeys, most of which have long, often prehensile tails used for balance and even gripping branches, a feature the bald uakari largely does without.
Why does the bald uakari live in flooded forest?
This species is closely associated with seasonally flooded rainforest habitat, moving between flooded and drier forest areas as water levels rise and fall throughout the year, tracking the seasonal availability of the seeds and fruit that make up its diet.
Why has the bald uakari declined?
This species has declined due to hunting and the loss of seasonally flooded rainforest habitat across parts of the western Amazon basin, pressures that have contributed to its classification as Vulnerable despite still forming relatively large social troops in remaining suitable habitat.