Action: Translocate (capture & release) wild primates from development sites to natural habitat elsewhere
- One study in Malaysia found that the majority of orangutans survived following translocation from a development site to natural habitat, alongside other interventions.
- Three before-and-after studies in Tanzania, French Guiana, and Madagascar found that a majority of primates survived for 5-30 months following translocation from a development site to natural habitat, alongside other interventions. One study in French Guiana found that a minority of primates survived for at least 18 months.
- One before-and-after study in India found that rhesus monkeys remained at the sites where they were released following translocation from a development site to natural habitat, alongside other interventions.
Supporting evidence from individual studies
A study in June-September 1993 in fragmented tropical forest in Sabah state, Malaysia found that 78 of 80 (98%) orangutans Pongo pygmaeus morio that were translocated from a development site to natural habitat elsewhere along with other interventions, survived capture and subsequent release at Tabin Wildlife Reserve. Four individuals escaped from their temporary holdings before they could be transported to the release site. Of these, three individuals suffered minor injuries and one individual sustained major injury during capture. Individuals were either immobilized in trees or captured manually on the ground with nets. Individuals underwent veterinary screens and sick animals were treated before they were released individually into habitat already occupied by resident orangutans. To avoid stress-related injuries, females were kept in separate (but adjacent) cages from their offspring and adequate space was maintained between occupied cages during temporary holdings and transportation. The study does not distinguish between the effects of the different interventions mentioned above.
A before-and-after trial in 1977-1996 in mixed tropical forest in Masingini Forest Reserve on Unguja Island, Tanzania found that groups of Zanzibar red colobus monkeys Procolobus kirkii survived translocation from an unprotected area to protected areas. Twenty-one of 23 translocated monkeys survived the three translocation events in 1977-1978. In 1981, 13 colobus monkeys were translocated into the Zanzibar Forest Reserve. A census in 1994 revealed the presence of 56-64 colobus monkeys, meanings a population increase of 56-78%. However, no statistical tests were carried out to determine whether this increase was significant. Monkeys were caught in nets and by hand while sleeping and were transferred directly to the release site. Surveys were conducted on eight partial days in 1991, 1994, 1995 and 1996. During another translocation of 13 colobus monkeys in 1978 to Kichwele Forest Reserve, two individuals died during the process and no surveys were conducted post-release.
A study in 1994-1995 in a primary forest at Petit Saut dam, French Guiana found that less than half of all red howler monkeys Alouatta seniculus that were translocated to natural habitat elsewhere along with other interventions, survived over 18 months. Of the 16 females that were monitored with radio-tags over 18 months, survival rate was 44-63%. Deaths related to translocation included screwworm fly larvae infestations under radio-collars (N=2) and trauma (N=1). Three females (19%) gave birth after release, but infants disappeared and probably died. All females studied for longer than three months (50%) settled within the release area. Of the 122 captured and translocated howlers from 28 different troops, ten out of 11 (91%) documented troops broke apart after release. Monkey groups were captured manually or with nets several months after the beginning of the flooding of the hydroelectric dam. All animals underwent veterinary screens before release in groups into habitat already occupied by the species. They were allowed to adapt to local habitat conditions before release. The study does not distinguish between the effects of the different interventions mentioned above.
A before-and-after trial in 1994-1995 in tropical forest near Petit-Saut dam, French Guiana found that most white-faced sakis Pithecia pithecia that were translocated from a development area to natural habitat nearby along with other interventions, survived for at least four months. Two out of three translocated sakis survived for at least four months after release; one individual died after circa 22 weeks. Sakis were captured during the flooding of their original habitat by nets. Three out of six translocated wild sakis where monitored over 41 weeks after their release, which took place one day after capture. The translocated sakis integrated with resident individuals. Monkeys were tagged with radio-transmitters and underwent veterinary screens prior to release as single individuals or as a group into a habitat already occupied by the species. Dead sakis were investigated to determine the cause of death. The study does not distinguish between the effects of the different interventions mentioned above.
A replicated, before-and-after-trial in 1995-2001 in temple orchards in Vrindaban, Mathura District, India found that rhesus monkeys Macaca mulatta translocated to nearby semi-natural, fragmented forest habitat along with other interventions, remained at their release sites for at least four years. A post-translocation study in 2001 confirmed that all of the 600 monkeys captured from 12 troops (45% of the total population) and translocated to eight different forest patches, had settled down, were healthy, showed no signs of stress, and behaved normally. The activity of one of the translocated groups (150 individuals) during the first three months post-release was similar to that of wild groups in northern India. No quantitative results were provided. Release sites were administrated by Social Forestry, and were selected based on the availability of food, water, shelter, and attitude of the local people. Captured monkeys, regarded as so-called ‘problem animals’ by local residents, were relocated to non-residential areas, where they were reintroduced in groups into habitat without resident rhesus monkeys. The study does not distinguish between the effects of the different interventions mentioned above.
A before-and-after trial in 2006-2007 in rainforest in Analamazaotra Special Reserve, Madagascar found that black-and-white ruffed lemurs (BWRL) Varecia variegata variegata and diademed sifakas Propithecus diadema survived for at least 30 months and reproduced after translocation from disturbed sites to undisturbed habitat along with other interventions. No mortalities were recorded for BWRL over a 30-month period and only one diademed sifaka died from natural causes. Two sets of BWRL twins (reproductive rate=57%) and seven diademed sifaka infants were born (reproductive rate=26%), the latter of which two survived. Seven BWRL and 27 diademed sifakas were captured at four disturbed forest sites and released in their social units to the reserve where the species had locally gone extinct and that included natural predators. Released primates were habituated to human presence and monitored with radio-collars. Two to eight months before the translocation was carried out, lemurs were darted and underwent veterinary checks. The study does not distinguish between the effects of the different interventions mentioned above.
- Andau PM, Hiong LK & Sale J.B. (1994) Translocation of pocketed orang-utans in Sabah. Oryx, 28, 263-268
- Struhsaker T.T. & Siex K.S. (1998) Translocation and introduction of the Zanzibar red colobus monkey: success and failure with an endangered island endemic. Oryx, 32, 277-284
- Richard-Hansen C., Vié J.C. & de Thoisy B. (2000) Translocation of red howler monkeys Alouatta seniculus in French Guiana. Biological Conservation, 93, 247-253
- Vié J., Richard-Hansen C. & Fournier-Chambrillon C. (2001) Abundance, use of space, and activity patterns of white-faced sakis (Pithecia pithecia) in French Guiana. American Journal of Primatology, 55, 203-221
- Imam E., Yahya H.S.A. & Malik I. (2002) A successful mass translocation of commensal rhesus monkeys Macaca mulatta in Vrindaban, India. Oryx, 36, 87-93
- Day S.R., Ramarokoto R.E.A.F., Sitzmann B.D., Randriamboahanginjatovo R., Ramanankirija H., Randrianindrina V.R.A., Ravololonarivo G. & Louis E.E.J. (2009) Re-introduction of diademed sifaka (Propithecus diadema) and black and white ruffed lemurs (Varecia variegata editorum) at Analamazaotra Special reserve, eastern Madagascar. Lemur News, 14, 32-37