Providing evidence to improve practice

Individual study: A reintroduction program for the conservation of the black howler monkey in Belize.

Published source details

Horwich R.H., Koontz F., Saqui E., Saqui H. & Glander K. (1993) A reintroduction program for the conservation of the black howler monkey in Belize. Endangered Species Research, 10, 1-6


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

Translocate (capture & release) wild primates from abundant population areas to non-inhabited environments Primate Conservation

A replicated study in 1992–1993 in tropical forest at Cockscomb Basin Wildlife Sanctuary (CWSB), Belize found that the majority of wild black howler monkeys Alouatta pigra captured and translocated to a site with no resident howlers along with other interventions, survived for at least ten months and reproduced. Twelve (86%) out of 14 reintroduced monkeys survived for at least ten months after release. One male and one juvenile disappeared two months post-release. Two infants were born in two of the three release groups, 3-8 months post-release. Howlers were captured at the Community Baboon Sanctuary (CBS), 100 km north of the CWSB. Tree species diversity overlapped by 60% between both locations. Prior to release, monkeys underwent veterinary screens. Three groups were released into habitat without resident howlers. They were allowed to adapt to local conditions before release. Six individuals were fitted with ball-chain radio-collars and six were implanted with radio-transmitters, but signals got lost six weeks post-release. The study does not distinguish between the effects of the different interventions mentioned above.

Reintroduce primates into habitat where the species is absent Primate Conservation

A replicated study in 1992–1993 in tropical forest in Belize found that the majority of reintroduced black howler monkeys Alouatta pigra that were released into habitat where no resident monkeys occurred, alongside other interventions, survived for at least ten months and reproduced. Twelve of 14 reintroduced monkeys (86%) survived for at least ten months after release. One monkey disappeared two months after release. Four infants were born in the release groups. Wild howlers had been captured at a sanctuary and were translocated to the site. Prior to release, monkeys were screened by vets. Monkeys were allowed to adapt to local habitat conditions before release. Six individuals were fitted with ball-chain radio collars and another six were implanted with radio-transmitters. Radio collars worked for 6-10 months, but transmitter signals were lost six weeks post-release. 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 replicated study in 1992-1993 in tropical forest at Cockscomb Basin Wildlife Sanctuary (CBWS) in Belize found that the majority of translocated black howler monkeys Alouatta pigra that underwent veterinary checks prior to release alongside other interventions, survived for at least ten months and reproduced. Twelve out of 14 reintroduced monkeys (86%) survived for at least ten months after release. One male and one juvenile disappeared two months post-release. Two infants were born, in each of two of the three release groups. Veterinary screens included blood tests and general health checks. Wild howlers had been captured at the Community Baboon Sanctuary and were translocated to CBWS. Three groups were released into habitat without resident howlers. They were allowed to adapt to local conditions before release. Six individuals were fitted with ball-chain radio-collars and six others were implanted with radio-transmitters. Radio-collars worked for 6-10 months, but transmitter signals got lost six weeks after 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 replicated study in 1992–1993 in tropical forest at Cockscomb Basin Wildlife Sanctuary (CBWS), Belize found that the majority of reintroduced black howler monkeys Alouatta pigra that were allowed to adapt to local habitat conditions prior to release along with other interventions, survived for at least ten months and reproduced. Twelve (86%) out of 14 reintroduced monkeys survived for at least ten months post-release. One male and juvenile disappeared two months post-release. Two infants were born in two of the three release groups, 3-8 months post-release. Howlers were kept in an 8 x 12 x 10 m enclosure for two days to acclimatize. Wild howlers were captured at Community Baboon Sanctuary and were translocated to CBWS. Prior to release, monkeys underwent veterinary screens. Three groups were released into habitat without resident howlers. Six individuals were fitted with ball-chain radio-collars and six were implanted with radio-transmitters, but transmitter signals got lost six weeks post-release. The study does not distinguish between the effects of the different interventions mentioned above.

Reintroduce primates in groups Primate Conservation

A replicated study in 1992–1993 in tropical forest at Cockscomb Basin Wildlife Sanctuary (CBWS) in Belize found that the majority of reintroduced black howler monkeys Alouatta pigra that were released in three groups alongside other interventions, survived for at least ten months and reproduced. Twelve out of 14 reintroduced monkeys (86%) survived for at least ten months post-release. One male and juvenile disappeared after two months. One group of four monkeys dissolved following aggressive interaction with another release group. One female dispersed with her infant and one female stayed alone. Two infants were born, in two release groups, 3-8 months post-release. Three groups, consisting of 3-7 individuals, were released 0.5-1 km apart into habitat without resident howlers. Wild howlers were captured at the Community Baboon Sanctuary and translocated to CBWS. Prior to release, howlers underwent veterinary screens. They were allowed to adapt to local conditions before release. Six individuals were fitted with ball-chain radio-collars and another six individuals were implanted with radio-transmitters. Radio-transmitter signals got lost six weeks after release. The study does not distinguish between the effects of the different interventions mentioned above.