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
Crab-eating macaque of populations due to increased wild trade and rising levels of human-macaque conflict, which are reducing overall population levels despite the species being widely distributed. Each subspecies faces differing levels of threats, and too little information is available on some subspecies to assess their conditions. The "M. f. umbrosa" subspecies is likely of important biological significance and has been recommended as a candidate for protection in the Nicobar Islands, where its small, native population has been seriously fragmented, and is listed as vulnerable on the IUCN Red List. The Philippine long-tailed macaque ("M. f. philippensis") is listed as near threatened,