Every year throughout Africa, primate rescue centers are flooded with chimpanzee orphans, primarily victims of the bushmeat trade. When adults are killed for meat the surviving infants are often offered for sale as pets, and those that get confiscated by law enforcement are taken to sanctuaries for care.
A new study, published in the International Journal of Primatology, examines 11 Pan African Sanctuary Alliance (PASA) member facilities, predicting their carrying capacity for chimpanzees and provides a roadmap for long term resource, infrastructure and financial planning.
Lead author Lisa Faust, PhD a research biologist with Chicago's Lincoln Park Zoo said, "The most sobering part of this study is realizing that most of these institutions already report being at capacity or close to capacity, and yet on average the group of sanctuaries are collectively faced with accepting 56 new chimpanzee arrivals every year, most of them under the age of two to three years old. Because chimpanzees are long-lived, this means that most of the sanctuaries will need to sustain or increase their current size, because they will continue to accept new arrivals as part of their commitment to chimpanzee welfare and law enforcement."
Chimpanzees are an endangered species, and while poaching is illegal it remains a major problem threatening their continued survival.
"PASA sanctuaries play a vital role in helping rescue and rehabilitate chimpanzees and other endangered primates, and that is our main objective," said Doug Cress, executive director of PASA. "But it's easy to get caught up in the day to day fight for survival and lose perspective. This study is so important because it allows us to step back and see where we'll be in the coming years and decades and to plan accordingly. Population modeling on this level is a wonderful tool."
A chimpanzee that survives the physical and emotional trauma of capture can take years to recover. But PASA member sanctuaries accept that long-term commitment, even if the only possible alternative to lifetime care -- reintroduction, the physical return of the chimpanzees back to the forest -- is a difficult and relatively new endeavor.
Chimpanzee reintroduction projects currently underway at PASA sanctuaries in Congo and Guinea have put more than 50 chimpanzees back into the wild, and three Cameroon sanctuaries are preparing to double that number through reintroduction programs in the next few years. But the cost, which can easily double a sanctuary's budget, is just one of the many obstacles to more widespread reintroduction.
"Reintroducing primates is not simple," Cress explained. "Deforestation and poaching make many areas unsuitable for reintroduction, and human encroachment has resulted in communities living in many of the national parks and protected areas. Also, it can be difficult to build a social group of chimpanzees that is physically and emotionally strong enough to survive a reintroduction. That's why the number of released animals remains relatively small compared to the number of orphans in need of care. Lifetime care in sanctuaries is the most frequent option for orphaned primates."
Chimpanzees can live up to 50 -- 60 years, so the commitment for lifetime care is substantial.
The study analyzed historic demographic patterns and projected future population dynamics of these select sanctuaries which housed (at that time) 760 chimpanzees. The median age was 9 years old, with 76 percent of the population being less than 15 years.
Lincoln Park Zoo chimpanzee behavioral researcher Steve Ross, PhD, co-author on the research, explained that as chimpanzees age and reach sexual maturity, group dynamics shift, making social structure an important component for future management plans for PASA sanctuaries.
"Older chimpanzees can be subject to aggression and social disharmony, especially in large groups," he explained. "This could be further exacerbated by the influx of adolescents, so managing group sizes and dynamics will be crucial for these sanctuaries."
"We found there to be an exponential relationship between population size and resource need because groups sizes cannot grow indefinitely," explained Faust. "Our goal with this research is to provide PASA with a road map for the potential future management challenges they may face. It should help long-term planning and increase their ability to be stewards for the apes they take in and advocates for those they work to protect in the wild."
The Great Ape Trust in Iowa also contributed to this study.
Materials provided by Lincoln Park Zoo. Note: Content may be edited for style and length.
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