|Scientific Name:||Ateles hybridus I. Geoffroy, 1829|
|Infra-specific Taxa Assessed:|
Ateles belzebuth ssp. brunneus Gray, 1872
|Taxonomic Notes:||The taxonomy of the spider monkeys is based on Kellogg and Goldman (1944) and Hill (1962). The forms hybridus, chamek and marginatus are listed as distinct species and A. fusciceps robustus Allen, 1914 is considered a junior synonym of A. f. rufiventris Sclater, 1871 following Heltne and Kunkel (1975) (see Rylands et al. 2000). Silva-López et al. (1996) argued that Ateles geoffroyi pan was not a valid taxon. Collins (1999) and Collins and Dubach (2000) argued strongly that hybridus I. Geoffroy, 1829 was distinct from belzebuth. Their position was reinforced by Nieves et al. (2005). Hernández-Camacho and Defler (1989) and Defler (2004) argued for the validity of the form brunneus Gray, 1872 from the Departments of Bolivar, Antioquia and Caldas, between the lower Ríos Cauca and Magdalena in Colombia. It is listed here as a subspecies of A. hybridus, as recommended by Defler (2004).|
|Red List Category & Criteria:||Critically Endangered A2cd+3cd ver 3.1|
|Assessor(s):||Urbani, B., Morales, A. L., Link, A. & Stevenson, P.|
|Reviewer(s):||Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)|
Listed as Critically Endangered as there is reason to believe the species has declined by at least 80% over the past 45 years (three generations) due primarily to hunting and habitat loss. Over the coming 45 years, this decline is likely to reach similar proportions due to continuing habitat loss.
|Previously published Red List assessments:|
|Range Description:||In Colombia, Ateles hybridus hybridus is found from the right bank of the Río Magdalena in the Departments of Magdalena, César (northward to the southern slopes of the Sierra Nevada de Santa Marta), the south-western portions of Guajira in the northernmost parts of the Serranía de Perijá, and in the middle Río Magdalena valley at least to the Departments of Caldas and Cundinamarca. There are also two populations of this subspecies on the slopes of the Cordillera Oriental of the Andes on the Venezuelan border: one population is found in the Río Catatumbo watershed in the Department of Norte de Santander and the other population is found in the north-east piedmont forest of the Department of Arauca (Hernández-Camacho and Cooper 1976; Defler 2003, 2004). |
The subspecies has a disrupted distribution in Venezuela (Mondolfi and Eisenberg 1979). It is located in the north, along the south-eastern part of the Central Mountain Range (Cordillera de la Costa) in the state of Miranda, and probably the state of Vargas. It is also located on both sides of the Venezuelan Andean Mountains (states of Zulia, Táchira, Mérida, Trujillo, Portuguesa, Apure and Barinas). In its eastern part, this primate is distributed on the piedmont forest and in the highly threatened lowland forests of San Camilo and Ticoporo. On the western side, it is also distributed in the piedmont of the Andes throughout the lowland areas of southern Lake Maracaibo to the Perijá Mountains (Sierra de Perijá) along the border with Colombia (Bodini and Pérez-Hernández 1987; Linares 1998; Cordero-Rodríguez and Biord 2001; Portillo and Velásquez 2006; Duque 2007; B. Urbani, unpubl.).
In Colombia, Ateles hybridus brunneus is found between the lower Cauca and Magdalena Rivers in the Department of Bolívar, Antioquia and Caldas. This population has sometimes been included with A. h. hybridus, but is here considered distinct.
Native:Colombia (Colombia (mainland)); Venezuela, Bolivarian Republic of (Venezuela (mainland))
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||In Colombia, Bernstein et al. (1976a) calculated a density of 9-14 individuals/km² for Ateles hybridus hybridus in the San Lucas mountains. Green (1978) calculated densities of 8.2-9.6 groups/km² at his study site, which if multiplied by his average group size (3.3 individuals) seems to suggest higher densities at his Cerro Bran site when compared with the other study site.|
There is no reliable population information available for Venezuela (B. Urbani pers. comm.).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||In Venezuela, Ateles hybridus hybridus inhabits mainly the high and lowland primary evergreen rainforests from 20 to 700 m asl. |
Spider monkeys travel and forage in the upper levels of the forest. They spend much time in the canopy and also use the middle and lower strata but are rarely seen in the understorey. In accordance with their use of the highest levels of the forest, they are highly suspensory. When travelling they spend more time hanging from branches, moving by brachiation and arm swinging, and climbing than they do walking or running on all fours. They are highly frugivorous and feed largely on the mature, soft parts of a very wide variety of fruits, which comprise 83% of their diet and are found mainly in the emergent trees and upper part of the forest canopy (Van Roosmalen and Klein 1988). They also eat young leaves and flowers (both especially at times of fruit shortage during the beginning of the dry season), and besides such as young seeds, floral buds, pseudobulbs, aerial roots, bark, decaying wood, and honey, and very occasionally small insects such as termites and caterpillars. They play a significant role as seed dispersers. Van Roosmalen (1985; Van Roosmalen and Klein 1988) found that A. paniscus was dispersing the seeds of at least 138 species (93.5% of all fruits species used) through their ingestion and subsequent defecation (endozoochory). A further 10 species were being dispersed by the monkeys carrying them off some distance from the tree before dropping them (exozoochory). In only 23 species were the seeds being ruined or eaten (seed predation).
Spider monkeys live in groups of up to 20-30 individuals (for review see Van Roosmalen and Klein 1988). However, they are very rarely all seen together, and nearly always to be found travelling, feeding and resting small in groups of varying size and composition, the only persistent association being that of a mother and her offspring (McFarland Symington 1990). Group members will also travel on their own. Each female in the group has a “core area” of the group’s home range which she uses most. Klein and Klein (1976, 1977) estimated 259-388 ha ranges with 20-30% overlap for A. belzebuth in La Macarena National Park, Colombia. Ateles are rarely seen in association with other primates and mostly they are occasional and ephemeral, resulting from the simultaneous occupation of fruiting trees.
Six estimated birth dates given by Klein (1971) for the closely related A. belzebuth, were spread throughout the year (December, January, April, September, October and November). Spider monkeys apparently reach sexual maturity at 4-5 years of age (Klein 1971; Eisenberg 1973, 1976). They give birth to single offspring after a long gestation period of 226-232 days, with a minimum theoretical interbirth interval in captivity of 17.5 months, but in the wild probably as long as 28-30 months (Eisenberg 1973, 1976).
Congdon (1996) provided a brief remark on the behaviour of these monkeys at the Reserva Forestal Caparo, and Duque (2007) provided a list of potential feeding trees for Ateles hybridus hybridus in the El Ávila National Park (however, this primate species was not observed at the time of Duque´s survey). Late maturation and long inter-birth intervals makes it difficult for them to recover from hunting and other threats.
Adult male weight 7.9-8.6 kg (mean 8.25 kg, n=2) (see Di Fiore and Campbell 2007
Adult female weight 7.5-10.5 kg (mean 9.1 kg, n=7) (see Di Fiore and Campbell 2007).
In Colombia, both Ateles hybridus hybridus and Ateles hybridus brunneus are subject to habitat loss and to hunting. The habitat of A. h. hybridus is extremely fragmented, and there may be few populations of an adequate size to be viable in the mid- to long-term (Defler et al. 2003).
Habitat alteration appears to be the most important threat to the Venezuelan population of A. h. hybridus. The lowland forest of the state of Zulia and the piedmond of the Perijá Mountains are heavily destroyed from expanding cattle-ranching activities (B. Urbani, unpubl.). Portillo and Velásquez (2006) undertook a gap analysis for this primate species within the Perijá Mountains and found that, while the total forest extent is still very large (813,257 ha), only 30% is relatively well preserved and protected. The rest remains affected by rapid human expansion and land clearance. Also in the Perijá Mountains, these monkeys seem to be favourite game animals (Lizarralde 2002). In central Venezuela, some areas that were reported with these monkeys (Cordero-Rodríguez and Biord 2001) were resurveyed by Duque (2007) without reports of any sightings; most of the area is already converted to secondary vegetation. Also in this region, B. Urbani (unpubl.) found that buffer areas around the protected areas—with confirmed populations of Ateles hybridus hybridus (P. N. Guatopo) and unconfirmed populations (M. N. Cueva Alfredo Jahn, P. N. Henry Pittier, P. N. San Esteban and P. N. El Ávila)—are transformed into cleared areas for slash-and-burn agriculture and human settlements as well as secondary forests. The lowland forest from the eastern part of the Andean Mountains, which are San Camilo and Ticoporo, are under severe pressure from logging.
Ateles hybridus hybridus is found in several protected areas in Colombia, including: Catatumbo-Bari National Natural Reserve (158,125 ha); Tamá National Natural Park (48,000 ha); El Cocoy National Natural Park (306,000 ha); and
Parque Nacional Sierra Nevada de Santa Marta (383,000 ha) (Defler 2004). They may also occur in Chingaza Natural National Park (50,374 ha).
In Venezuela, the species occurs in the Guatopo National Park (92,640 ha), which is of particular importance because it is one the major water reservoirs for the capital city, Caracas. The Sierra de Perijá National Park (295,288 ha) is the other major protected area with brown spider monkeys. In these national parks, enforcement against hunting and wood extraction is needed. There are no NGOs working actively with Ateles hybridus hybridus as target species, and governmental agencies should improve their conservation efforts. However, there is interest for continuing with surveys on these primates especially in central Venezuela as well as an awareness programme particularly at a local level. It is also fundamental to increase the number of park rangers and improving their economical condition. They also occur in Caparo Forest Reserve (Venezuela) (B. Urbani pers. comm.).
Bernstein et al. (1976a) showed the effect of forest disturbance, especially on A. h. brunneus (and Lagothrix lugens), and (1976b) made a plea for the establishment of reserves for this and other threatened primate taxa. Fortunately, the Serranía de San Lucas in southern Bolívar still contains extensive forest which has been identified as a possible national park site. The establishment of a San Lucas National Park ought to have high priority in Colombia, since it would preserve many elements of the Nechí refugium, including Saguinus leucopus and Lagothrix lugens. However, the presence of political insurgents, the military and some mine fields make the region very difficult for work and for the presence of the government. The Cienaga de Barbacoas represents another priority area for consideration for the creation of a protected area.
Censuses are required for a better understanding of the status of Ateles hybridus, and local populations need to be clearly identified and actively managed, something that is not taking place even in the protected areas where A. h. hybridus is known to occur.
This species is listed on Appendix II of CITES.
|Citation:||Urbani, B., Morales, A. L., Link, A. & Stevenson, P. 2008. Ateles hybridus. The IUCN Red List of Threatened Species 2008: e.T39961A10280054.Downloaded on 22 March 2018.|