Rhesus macaque baby. The baby was later found dead in a well. Though monkeys are known to attack people, enter homes or damage property, this reported behaviour was unusual. The rhesus macaque is well known to science. Due to its relatively easy upkeep in captivity, wide availability, and closeness to humans anatomically and physiologically, it has been used extensively in medical and biological research on human and animal health-related topics. It has given its name to the Rh factor, one of the elements of a person's blood group, by the discoverers of the factor, Karl Landsteiner and Alexander Wiener. The rhesus macaque
Celebes crested macaque Paignton Zoo are among a number of mostly European zoos which hold "ex-situ" breeding populations of this animal. Since 2006, the "Macaca Nigra Project" has been studying the biology and promoting the conservation of this species. The project, a collaboration between the German Primate Center and the Bogor Agricultural Institute, is run by Antje Engelhardt and located in the Tangkoko reserve, home of the biggest crested macaque population remaining in the species' original distribution range. Nevertheless, despite being critically endangered, crested black macaque are still being hunted down and slaughtered. Crested black macaque is considered a delicacy by local residents.