Providing evidence to improve practice

Action: Captive breeding and reintroduction of primates into the wild: born and reared in cages Primate Conservation

Key messages

  • One before-and-after study in Brazil found that most reintroduced golden lion tamarins that were born and reared in cages, alongside other interventions, did not survive over seven years or had a higher mortality than wild-born tamarins.
  • One controlled study in French Guiana found that more squirrel monkeys which were born and reared in cages, alongside other interventions, died or were returned to captivity post-reintroduction compared to wild-born monkeys.
  • One controlled study in Madagascar found that the diet of reintroduced black-and-white ruffed lemurs which were born and reared in cages, alongside other interventions, did not overlap with that of wild lemurs.

Supporting evidence from individual studies

1 

A before-and-after trial in 1984-1991 in coastal forest in Poço das Antas Reserve, Brazil  found that over 60% of captive-bred golden lion tamarins Leontopithecus rosalia that were reintroduced into the wild alongside 14 other interventions, did not survive over seven years. Fifty-eight (64%) out of 91 reintroduced tamarins did not survive in the wild. However, 57 infants were born (reproductive rate=63%) during this period, of which 38 (67%) survived. In contrast to the wild-born orphaned tamarins, captive-born tamarins never became independent of food and water provisioning and daily management. Captive-bred or orphaned tamarins were introduced in different years into habitat already occupied by the species and predators. Some groups were trained in behaviours that facilitate survival, were provided supplementary food, water and nesting boxes, and allowed to adapt to local conditions before release. Tamarins were quarantined, underwent veterinary checks and were treated for parasites before release. Sick or injured animals were rescued, treated and re-released. The reserve became officially protected in 1983. The study does not distinguish between the effects of the different interventions mentioned above.

2 

A controlled study in 1984-1991 in coastal forest in Poço das Antas Reserve, Brazil found that more wild-born lion tamarins Leontopithecus rosalia survived after reintroduction into the wild than captive-bred tamarins. No statistical tests were carried out to determine whether this difference was significant. Twenty-nine (34%) of 85 and four (67%) of six reintroduced captive-bred and wild-born tamarins were still alive in 1991, respectively. Captive-bred and wild-born animals survived for between 1-83 months and 43-75 months, respectively. Furthermore, captive-born tamarins depended on daily provisioning and health monitoring whereas wild-born tamarins were independent of supplementary food or managing. Wild-born tamarins had been taken by poachers and lived in private homes before they were confiscated. Captive-bred tamarins were retrieved from the National Zoological Park in Washington DC and transferred to the Rio de Janeiro Primate Centre before release.

3 

A controlled study in 1998-1999 in tropical forest on an island in French Guiana found that wild-born squirrel monkeys Saimiri sciureus survived for at least 15 weeks, whereas all captive-born monkeys either died or were returned to captivity. All of six wild-born monkeys survived for at least 15 weeks. In contrast, three out of eight captive-born monkeys died and five were returned to captivity. Two individuals died of starvation in release cages, and another was probably killed by resident wild monkeys. One month after release, the remaining five captive-born monkeys were captured and brought back to captivity.

4 

A controlled study in 1998-2001 in tropical forest in Betampona Reserve, Madagascar found that diets of captive-bred, reintroduced black-and-white ruffed lemurs Varecia variegata variegata that were born and reared in cages along with other interventions, did not overlap with that of the resident wild group in the first year after release. Captive-bred lemurs (one male and two females) fed only on approximately half of the plant species (N=57) that the wild group (ten individuals) fed on (N=109). Captive-bred lemurs did not closely follow the dietary choices and seasonal changes exhibited by the wild group, although no statistical tests were carried out to determine whether this difference was significant. Reintroduced lemurs were born and raised in cages at zoos and had limited (several months) free-ranging experience at a sanctuary before release. They were released in groups into habitat already occupied by the species and were provided with supplementary food during three years. 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. and Sutherland, W.J. (2017) Primate conservation: Global evidence for the effects of interventions. University of Cambridge, UK