Providing evidence to improve practice

Individual study: Group release of sanctuary chimpanzees (Pan troglodytes) in the Haut Niger National Park, Guinea, West Africa: ranging patterns and lessons so far

Published source details

Humle T., Colin C., Laurans M. & Raballand E. (2011) Group release of sanctuary chimpanzees (Pan troglodytes) in the Haut Niger National Park, Guinea, West Africa: ranging patterns and lessons so far. International Journal of Primatology, 32, 456-473


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Reintroduce primates into habitat with predators Primate Conservation

A before-and-after trial in 2008–2010 in dry forest in Haut Niger National Park, Guinea found that the majority of wild-born orphaned western chimpanzees Pan troglodytes verus that were reintroduced into habitat with predators, along with other interventions, survived reintroduction and remained free-living for at least 27 months. One of 12 released chimpanzees died after failing to recover from anaesthesia during a recovery mission. One female returned to the sanctuary voluntarily and one male was returned after suffering injuries during another recovery mission. Five chimpanzees remained together at the release site and two infants were born both of which survived. Another female immigrated into a wild chimpanzee community and three chimpanzees moved to an area away from the release site. Although predators are present in the forest no observations of attacks on chimpanzees were made. Before release chimpanzees were screened for diseases and some chimpanzees were allowed to acclimatize to local habitat conditions. Chimpanzees were initially supplemented with food on a daily-, and later on, a weekly basis. The study does not distinguish between the effects of the different interventions mentioned above.

Provide supplementary food for a certain period of time only Primate Conservation

A before-and-after trial in 2008-2010 in forest-savanna in Haut Niger National Park, Guinea found that the majority of wild-born orphaned western chimpanzees Pan troglodytes verus that were supplemented with food for a certain period of time along with other interventions, survived reintroduction and remained free-living over 27 months. One out of 12 released chimpanzees died from anaesthesia during a recovery mission. One female returned to the sanctuary voluntarily and one male was returned after suffering injuries. Two females gave birth and both offspring survived. Another female integrated into a wild chimpanzee community and three chimpanzees moved to a new area. Although nutritionally independent, chimpanzees were initially supplemented with food on a daily-, and later on, a weekly basis to encourage them to remain in the area and to facilitate visual monitoring. All chimpanzees were screened for diseases before their collective release into habitat with wild chimpanzees and predators. Some chimpanzees were allowed to acclimatize to local habitat conditions prior to release. The study does not distinguish between the effects of the different interventions mentioned above.

Allow primates to adapt to local habitat conditions for some time before introduction to the wild Primate Conservation

A before-and-after trial in 2008-2010 in forest-savanna mosaic in Mafou forest, Haut Niger National Park, Guinea found that the majority of wild-born orphaned western chimpanzees Pan troglodytes verus, some of which were allowed to acclimatize to local habitat conditions prior to release along with other interventions, survived reintroduction and remained free-living for at least 27 months. Only one of 12 released chimpanzees died after anaesthesia during a recovery mission. One female returned to the sanctuary voluntarily and one male was returned after suffering injuries. Five chimpanzees remained together at the release site and two females gave birth to an infant, both of which survived. Another female immigrated and integrated into a wild chimpanzee community and three chimpanzees moved to an area away from the release site. Five adult males were held in an enclosure (1.5 ha) with an annex cage (25 m2) for 1-4 months prior to release. All chimpanzees were screened for diseases before their collective release into habitat with wild chimpanzees and predators. Chimpanzees were initially supplemented with food on a daily-, and later on, a weekly basis. The study does not distinguish between the effects of the different interventions mentioned above.

Conduct veterinary screens of animals before reintroducing/translocating them Primate Conservation

A before-and-after trial in 2008-2010 in forest-savanna mosaic in Mafou forest in Haut Niger National Park, Guinea found that the majority of wild-born orphaned western chimpanzees Pan troglodytes verus that underwent veterinary screens prior to release alongside other interventions, survived reintroduction and remained free-living for at least 27 months. Only one out of 12 (8.3%) released chimpanzees died from anaesthesia during a recovery. One female returned to the sanctuary voluntarily and one male was returned after suffering injuries during another recovery mission. Five chimpanzees (42%) remained together at the release site and two females gave birth to an infant, both of which survived. Health checks included examination of faecal samples for parasites, tuberculosis tests and haematological and serotological analyses. All chimpanzees were released together into habitat with resident wild chimpanzees and predators. Some chimpanzees were allowed to acclimatize to local habitat conditions prior to release. Chimpanzees were initially daily supplemented with food and later on, weekly. The study does not distinguish between the effects of the different interventions mentioned above.

Reintroduce primates into habitat where the species is present Primate Conservation

A before-and-after trial in 2008–2010 in dry forest in Guinea found that the majority of wild-born orphaned western chimpanzees Pan troglodytes verus that were reintroduced into habitat with wild chimpanzees along with other interventions, survived reintroduction and remained free-living for at least 27 months. One (8.3%) of the 12 released chimpanzees died. One female returned to the sanctuary voluntarily and one male was returned after suffering injuries during a recovery mission. Five chimpanzees (42%) remained together at the release site. Two infants were born, both of which survived. Another female immigrated and integrated into a wild chimpanzee community and three chimpanzees moved to an area away from the release site. One male was observed to have suffered injuries to his genitals and face that were presumably inflicted by resident wild chimpanzees. All reintroduced chimpanzees were screened for diseases before their release into habitat with predators. Some chimpanzees were allowed to acclimatize to local habitat conditions prior to release. Chimpanzees were initially supplemented with food on a daily-, and later on, a weekly basis. The study does not distinguish between the effects of the different interventions mentioned above.

Reintroduce primates in groups Primate Conservation

A before-and-after trial in 2008-2010 in dry forest-savanna mosaic in Mafou forest, Haut Niger National Park, Guinea found that the majority of wild-born orphaned western chimpanzees Pan troglodytes verus that were reintroduced in a group along with other interventions, survived reintroduction and remained free-living for at least 27 months. One out of 12 (8.3%) released chimpanzees died from anaesthesia during a recovery mission. One female returned to the sanctuary voluntarily and one male was returned after suffering injuries. Five chimpanzees (42%) remained together at the release site and two females gave birth and both infants survived. Another female dispersed to a wild chimpanzee community and three chimpanzees moved to an area away from the release site. Chimpanzees were released simultaneously from release cages (5 adult males) or individual transport cages ca. 100 m away (6 females, 1 young male). All chimpanzees were screened for diseases before their release into habitat with wild chimpanzees and predators. Chimpanzees were initially daily supplemented with food, and later on, a weekly . The study does not distinguish between the effects of the different interventions mentioned above.