The common, or Humboldt’s, Woolly Monkey (Lagothrix lagotricha), one of the chunkiest and heaviest New World primates, lives in the rainforests of the Western Amazon river basin, including the CTF supported Reserves at Uwasu in Western Brazil and Jatun Sacha in Eastern Ecuador.
Reserves such as these are critical for the survival of these monkeys. They inhabit river edge gallery forest; palm woodland; seasonally flooded varzea and dry terra firma primary forest; and high altitude cloud forest. They prefer mature, continuous, undisturbed humid tracts – and will not live in secondary woodland which has re-grown after logging.
Covered in short, dense fur, they have large, round heads with a bare black or brown face. Their bodies are thick, with sturdy limbs, and their protruding bellies have given them the Portuguese name ‘barrigudo’ or ‘big belly’. They average 16–24 inches in length (40–60 cms), excluding their thick and prehensile tail.
They are active during the day – and gregarious – living in social groups of 10 to 70, often in company with capuchins, howlers and other species of monkeys. Rather slow moving, they generally travel on all fours, but often swing by their hands, feet and tail – or by the tail alone. On the ground, they can stand erect using their tail for support, but they are happiest in the forest mid-canopy at 7–12 metres (22–38 feet).
Their principal food is ripe fruit, supplemented by leaves, seeds and some insects. Seeds are most important early in the rainy season when ripe fruit is not readily available. Most intensively hunted Females reach maturity at 6–8 years and males any time after 5 years. Females bear single young after a 7–8 months gestation period and feed their babies for 9–12 months. The young are carried for the first month or so on the abdomen of the mother and climb onto her back after 6 weeks.
It is at this time that woolly monkeys are at their most vulnerable. They are the most intensively hunted primate species in South America – a mother normally being killed so that her infant can be sold on the pet market. Tragically, it is estimated that ten mothers are sacrificed for every live individual infant that actually reaches the market.
Groups of young woollies are very playful in the wild, while grooming is a common activity within a social group. Adult males receive the most grooming, whilst adult females are usually groomed by their juvenile daughters. Communication is by voice, facial expression and other visual behaviour and woollies can show subtle changes in mood and intention by employing a variety of expressions.
Restricted to the Western Amazon basin of Northern South America, common woolly monkeys occur in the upper Magdalena River valley in Colombia; throughout much of the upper Amazon basin of Colombia, Ecuador, Peru and Bolivia; in Brazil west of the Rio Negro; and in the foothills and Eastern slopes of the Andes up to 3,000 metres.
And Michael McColm considers ‘that the 3150 hectare Bilsa Biological Station continues to be the only sustainable and viable conservation initiative in the Mache-Chindul region’. The Foundation is seeking funding for forested properties within the Bilsa Boundary, which, all together, total about 250 hectares. But the 24 hectares that has just been secured by the CTF donation was the most urgent.
It is Pre-Montane Tropical Wet Forest – probably the rarest forest type in Western Ecuador with less than 1% remaining. The purchase will connect two existing important tracts of this type of forest inside the boundaries of the Bilsa Station. The forest is along the higher ridge-line of the Reserve and at this elevation provides habitat and protection for Jaguars, the exotic Long-Wattled Umbrella-bird and the rare, large and striking Banded Ground-Cuckoo as well as watershed protection for the Dogola River.
This river is one of the few in Western Ecuador still surrounded by forest habitat and protects a correspondingly high level of unique endemic fish species – species found in no other coastal river in the region.
The Bilsa Biological Station’s biodiversity credentials are certainly impeccable. Two thousand different plant species have been documented, including 30 species completely new to science. Abundant animal and bird populations indicate an intact ecosystem. To date, 24 mammal species are known to live in Bilsa, five of which are on international threatened species lists. Apart from the jaguar, these are the jaguarundi, oncilla, giant anteater and troupes of mantled howler monkeys.
More than 300 species of birds have been documented, amongst the highest totals for any Western coastal forest in Ecuador. But once again, it is the uniqueness of many of the birds which makes Bilsa so special. It is listed as a key area for the protection of birds in both the Choco and Tumbesian endemic bird areas (confined respectively to Ecuador and Colombia and Ecuador and Peru), which between them hold 96 species of birds found nowhere else in the World.
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