Crab-eating macaque 27% animal matter, 15% flowers and other plant matter, and 14% food provided by humans. This species exhibits particularly low tolerance for swallowing seeds. Despite their inability to digest seeds, many primates of similar size swallow large seeds, up to , and simply defecate them whole. The crab-eating macaque, though, spits seeds out if they are larger than . This decision to spit seeds is thought to be adaptive; it avoids filling the monkey’s stomach with wasteful bulky seeds that cannot be used for energy. It also can help the plants by distributing seeds to new areas: Crab-eating macaques eat
Arunachal macaque and 3500 m above sea level, making it one of the highest-dwelling primates. It belongs to the "M. sinica" species-group of macaques, along with the Assamese macaque ("M. assamensis"), the Tibetan macaque ("M. thibetana"), the bonnet macaque ("M. radiata") and the toque macaque ("M. sinica"). The Arunachal macaque is apparently physically similar to the Assam and Tibetan macaques, while genetically closely related to the bonnet macaque of southern India. This is probably the result of convergent evolution, where organisms evolve similar physical features due to similar environmental selection pressure, while genetically they may have different origins. However, its full specific