|Scientific Name:||Alouatta discolor (Spix, 1823)|
|Taxonomic Notes:||Hill (1962) listed five subspecies of the red-handed howler monkey, Alouatta belzebul: A. b. belzebul (Linnaeus, 1766) (restricted by Cabrera  to the Rio Capim, eastern Pará); A. b. discolor (Spix, 1823) from Gurupá, Pará; A. b. ululata Elliot, 1912, from Miritiba, Maranhão; A. b. mexianae Hagmann 1908, from the island of Mexiana, in the Marajó Archipelago, Brazil; and A. b. nigerrima Lönnberg, 1941 (restricted by Cabrera  to Patinga, Amazonas).
Whereas Groves (2001, 2005) considered A. discolor (Spix, 1823) and A. ululata Elliot, 1912, to be synonyms of A. belzebul, Gregorin (2006) placed them as distinct species, followed here.
|Red List Category & Criteria:||Vulnerable A2c ver 3.1|
|Assessor(s):||Boubli, J.-P., Di Fiore, A., Rylands, A.B. & Mittermeier, R.A.|
|Reviewer(s):||Mittermeier, R.A., Rylands, A.B. (Primate Red List Authority) & Hoffmann, M. (Global Mammal Assessment Team)|
This species is listed as Vulnerable given that it is estimated to have undergone a decline exceeding 30% over the past 3 generations (36 years) due to intensive and ongoing habitat loss.
|Previously published Red List assessments:|
|Range Description:||The type locality for Alouatta discolor is given as Forte Curupá (= Gurupá), Pará, Brazil. Gregorin (2006) explained that this was on the southern margin of the Rio Amazonas, not on the Island of Gurupá (opposite), which is occupied by red howler (Fernandes 1994), presumably Alouatta macconnelli. It would seem that this would be the easternmost limit to the range of this species, whjch extends west in a narrow strip along the south bank of the Rio Amazonas and south through the interfluvium bounded by the rios Tapajós and Juruena in the west and the rios Xingu and Iriri in the east (Gregorin 2006). Alouatta discolor is the howler monkey of the Rio Curuá basin. |
Bonvicino et al. (1989) indicated that Alouatta discolor occurs on the Islands of Marajó and Caviana, and Mexiana, but here we follow Fernandes (1994), Ferrari and Lopes (1996), and Gregorin (2006) who agree that Alouatta belzebul is the howler occurring there.
Between the lower Xingu in the west and the Tocantins the identity of this species is in doubt (A. Rylands, pers comm.).
Native:Brazil (Mato Grosso, Pará)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are no published density estimates available.|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||This species is found in lowland terra firma and seasonally inundated rain forest.|
The howler monkeys are the large leaf-eaters of the South American primate communities. The molar teeth are particularly adapted for their chewing leaves through shearing. Like the spider monkeys, they are prehensile-tailed, with a naked patch of skin on the under surface at the tip. Their most characteristic feature is the deep jaws which surround the enlarged larynx and hyoid apparatus, a resonating chamber. It is with this enlarged and highly specialized voice box that they produce their howls (grunts, roars and barks). Howling sessions, usually involving the entire group, can be heard particularly in the early morning and are audible at distances of 1-2 kms (Drubbel and Gautier 1993).
Fourteen is a large group, and they can usually be seen numbering four or five or up to 11 or so individuals. There is usually only one dominant male in the group (occasionally two), others being sub-adults, or juveniles, along with a harem of two to five females. Unlike the spider monkeys, and related to the large proportion of leaves in the diet (up to 50% of the annual diet), the howler monkeys generally have quite small and broadly overlapping home ranges, of 5 ha up to 45 ha, depending on the type of habitat (Neville et al. 1988). Pinto (2002a,b; Pinto and Setz 2004) studied a group of 7-9 animals in northern Mato Grosso that used a home range of 63 ha.
Howlers are the only New World primates which regularly include mature leaves in their diet, although softer, less fibrous, young leaves are preferred when they are available. Their folivory and ability to eat mature leaves is undoubtedly one of the keys to their wide distribution and the wide variety of vegetation types they inhabit. Mature fruit is the other important food item, especially wild figs (Ficus) in many regions, but they also eat leaf petioles, buds, flowers (sometimes seasonally very important), seeds, moss, stems and twigs, and termitaria.
Size: As for Alouatta belzebul
Adult male weight 7.27 kg (n=27) (Peres 1994)
Adult female weight 5.52 kg (n=26) (Peres 1994).
|Major Threat(s):||Both deforestation and hunting occur throughout the range. Extensive deforestation is being driven by logging, cattle ranching and industrial soy plantations - accompanying the Cuiabá-Santarém highway, which bisects its range (north to south) and the Transamazon highway which bisects its range west to east. The paving of these results in deforested swathes 50 to 100 km wide on either side of the road. There is also some limited subsistence hunting.|
The following protected areas are within the range of the species: Tapajós National Forest (600,000 ha); Itaituba I National Forest (220,034 ha); Itatiuba II National Forest (440,500 ha); and Altamira National Forest (689,012 ha).
It is listed on Appendix II of CITES.
|Citation:||Boubli, J.-P., Di Fiore, A., Rylands, A.B. & Mittermeier, R.A. 2008. Alouatta discolor. The IUCN Red List of Threatened Species 2008: e.T43912A10836686.Downloaded on 13 December 2017.|