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 at the top of the head are remarkable features. It has an "apelike" appearance due to its almost non-existent, non-visible, vestigial tail stub of only approximately . With a total body length of to and a weight of to , it is one of the smaller macaque species. Its life expectancy is estimated at approximately 20 years in the wild. The Celebes crested macaque is a diurnal rain forest dweller. This macaque is primarily terrestrial, spending more than 60% of its day on the ground foraging for food and socializing, while sleeping and searching for food in the trees. The