Providing evidence to improve practice

Individual study: Reintroduction of black howler monkeys (Alouatta pigra) into the Cocksomb Basin Wildlife Sanctuary, Belize.

Published source details

Koontz F., Horwich R.H., Saqui S., Saqui H., Glander K., Koontz C. & Westrom W. (1994) Reintroduction of black howler monkeys (Alouatta pigra) into the Cocksomb Basin Wildlife Sanctuary, Belize. American Zoo and Aquarium Association annual Conference Proceedings, Bethesda, MD, 104-111.


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

Implement multimedia campaigns using theatre, film, print media, discussions Primate Conservation

A before-and-after study in 1992-1994 in tropical forest in Cockscomb Basin Wildlife Sanctuary, Belize found that a population of wild black howler monkeys Alouatta pigra translocated into an area where the local human community was educated about this project by multimedia campaigns alongside other interventions, increased by 61% over three years. The black howler population increased from 62 in 1994 to >100 individuals in 1997. No statistical tests were carried out to determine whether this increase was significant. One-month-, 6-month-, 1-year, and 2-year survival rates for the different cohorts released in the dry seasons of 1992, 1993, and 1994, was 81-100%. Birth rate was 20% (n=12) and infant survival rate was 75% (n=9). Education campaigns used TV, radio, print media, lectures and discussions. Entire howler social groups were reintroduced together, and ten of the 14 groups were held in cages for 1-3 days before release with a distance of 700-1000 m to the neighbouring troop. All individuals were individually and permanently marked, and adults were fitted with radio-collars. Hunting was largely controlled in the sanctuary since its establishment. The study does not distinguish between the effects of the different interventions mentioned above.

Implement local no-hunting community policies/traditional hunting ban Primate Conservation

A before-and-after trial in 1992-1994 in tropical forest in Cockscomb Basin Wildlife Sanctuary in Belize found that the black howler monkey Alouatta pigra population that was reintroduced into an area where hunting was largely controlled along with other interventions, showed an increase in size over time. The population increased from 62 in 1994 to >100 individuals (61% increase) in 1997. No statistical tests were carried out to determine whether this difference was significant. One-month-, 6-month-, 1-year, and 2-year survival rates for the different cohorts released in the dry seasons of 1992, 1993, and 1994, was 100%, 92%, 81%, and 86%, respectively. Birth rate was 20% (n=12) and infant survival rate was 75% (n=9). Entire social groups were reintroduced at once, and ten of the 14 groups were held in cages for 1-3 days before release within 700-1000 m to the neighbouring troop. All individuals were permanently marked, and adults were fitted with telemetry collars. The local community was educated about the reintroduction project and black howler conservation by implementing multimedia campaigns. 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 1992–1997 in tropical forest in Belize found that the population wild black howler monkeys Alouatta pigra that was reintroduced, alongside other interventions, increased over time. No statistical tests were carried out to determine whether this increase was significant. Survival rate for monkeys reintroduced in 1992–1994 after between one month and 2 years was 86–100%. Birth rate was 20% (12 monkeys) and infant survival rate was 75% (9 of 12 monkeys). After 5 years, the population had increased from 62 to >100 individuals. Social groups were reintroduced, and 10 of the 14 groups were held in cages before release into habitat. Before release all individuals were screened by vets, were individually and permanently marked, and adults were fitted with telemetry collars. Hunting was largely controlled in the area and the local community was educated about conservation through multimedia campaigns. 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 1992-1997 in tropical forest in Cockscomb Basin Wildlife Sanctuary in Belize found that the population of introduced wild black howler monkeys Alouatta pigra that underwent extensive veterinary screens before release into the wild along with other interventions, increased in size over time. By 1997, the population increased by 61% (62 to >100 individuals). No statistical tests were carried out to determine whether this increase was significant. One-month-, 6-month-, 1-year, and 2-year survival rates for the different cohorts released in the dry seasons of 1992, 1993, and 1994, were 81-100%. Birth rate was 20% (n=12) and infant survival rate was 75% (n=9). Entire social groups were reintroduced at once over a two-year period. Ten of the 14 groups were held in cages for 1-3 days before release with a distance of 700-1000 m to the neighbouring troop. All individuals were permanently marked and adults were radio-collared. Hunting was largely controlled in the sanctuary and the local community was educated about the reintroduction project and black howler conservation through multimedia campaigns. 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 1992-1994 in tropical forest in Cockscomb Basin Wildlife Sanctuary in Belize found that a reintroduced population of black howler monkeys Alouatta pigra that was allowed to adapt to local habitat conditions before release into the wild along with other interventions, increased in size over time. By 1997, the population had increased by 61% (62 to > 100 individuals). No statistical tests were carried out to determine whether this increase was significant. One-month-, 6-month-, 1-year, and 2-year survival rates for the different cohorts released in the dry seasons of 1992-1994, were 81-100%. Birth rate was 20% (N=12) and infant survival rate was 75% (N=9). Entire social groups were reintroduced at once, and ten of the 14 groups were held in cages for 1-3 days before release with a distance of 700-1000 m to the neighbouring troop. All individuals underwent veterinary screens, were permanently marked, and adults were radio-collared. Hunting was largely controlled and the local community was educated about black howler conservation. 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 1992-1994 in tropical forest in Cockscomb Basin Wildlife Sanctuary in Belize found that the population of wild black howler monkeys Alouatta pigra that was reintroduced in groups alongside other interventions, increased by more than 60% in five years. By 1997, the population had increased from 62 to 100 individuals. However, no statistical tests were carried out to determine whether this increase was significant. One-month to 2-year survival rates for the different cohorts released in the dry seasons of 1992-1994, were 81-100%. Birth rate was 20% (N=12) and infant survival rate was 75% (N=9). Entire social groups were reintroduced together, and ten of the 14 groups were held in cages for 1-3 days before release into habitat without predators and with a distance of 700-1000 m to the neighbouring troop. All individuals underwent veterinary screens, were individually marked, and adults were fitted with radio-collars. Hunting was largely controlled in the sanctuary and the local community was educated about the reintroduction project and the importance of black howler conservation through multimedia campaigns. The study does not distinguish between the effects of the different interventions mentioned above.