Bald-headed uakari  (Cacajao calvus)

These bizarre-looking monkeys have bright crimson bald faces (2). For South American primates they have particularly short tails (5) and broad, flat faces (4). Four different subspecies are recognised and these exhibit different coat colourations, ranging from the pale orange/white coat of the white bald-headed uakari (Cacajao calvus calvus) to the red coat and pale shoulders of the red bald-headed uakari (C. c. rubicundus) (4). C. c. ucayalii has a reddish-golden coat with black markings on the upper surface of the tail, whilst C. c. novaesi has a more orange tone with pale-coloured shoulders (4). Malaria is an important disease in some parts of the Amazon rainforest and it is thought that these monkeys may have evolved bright red faces as a symbol of a healthy individual; monkeys who have contracted the disease are noticeably paler and are not chosen as sexual partners as they do not have the desired natural immunity to malaria (6).

Found in the Amazon basin (2) in Brazil, Peru and Columbia (1). Of the subspecies, only C. c. ucayalii is found in Peru, the others are found in Brazil, whilst the red bald-headed uakari is also found in Columbia (1).

Bald-headed uakaris are found in areas of tropical rainforest that undergo flooding (5).

Bald-headed uakaris are found in large multimale-multifemale groups, which may number up to 100 individuals although these larger troops are themselves composed of smaller, mixed groups (5). Females give birth to a single offspring between December and March; infants are initially carried on their mother's front before being transferred to her back to be transported through the treetops (5).

Fruit makes up the majority of the uakari diet, although they will also consume buds, leaves and insects (5). These monkeys are active during the day and spend most of their time in the trees, only alighting on the ground to search for food in the leaner times of the dry season (5).

Habitat destruction and hunting are the main causes of the decline in bald-headed uakari numbers. These monkeys are hunted in many parts of Peru and Brazil, either for meat or as bait; their riverine forest habitat makes them particularly vulnerable to hunting from canoes (1).

Very few effective protection measures exist to preserve the future of the bald-headed uakari, although the species is protected by law in Peru (7). Further information on the natural ecology and distribution of this species is urgently needed before effective conservation measures can be put in place.

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