Conservation Evidence strives to be as useful to conservationists as possible. Please take our survey to help the team improve our resource.

Providing evidence to improve practice

Action: Reintroduce primates into habitat without predators Primate Conservation

Key messages

  • One study in Tanzania found that a population of reintroduced chimpanzees increased over 16 years following reintroduction into habitat without predators.

Supporting evidence from individual studies


A study in 1966–1985 on a forested island in Rubondo National Park, Tanzania found that eastern chimpanzees Pan troglodytes schweinfurthii reintroduced into habitat devoid of predators along with other interventions, bred and increased in numbers from 17 to at least 20 individuals over 16 years. No statistical tests were carried out to determine whether this increase was significant. At least two males were shot after attacking game scouts. Two new-born infants were observed in 1968 and in 1985. All of the 17 reintroduced chimpanzees had been born in the wild and had spent time in captivity. Their age at the time of release varied from four to 12 years. Chimpanzees were released in four lots (from 1966 to 1969). Chimpanzees in the first release group were provided with supplementary food for two months. The study does not distinguish between the effects of the different interventions mentioned above.

Referenced papers

Please cite as:

Junker, J., Kühl, H.S., Orth, L., Smith, R.K., Petrovan, S.O. & Sutherland, W.J. (2018) Primate conservation. Pages 393-445 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2018. Open Book Publishers, Cambridge, UK.