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
Rhesus macaque significance because the macaque is used as an experimental model of the human immune system. In humans, the preferentially expressed antigen of melanoma (PRAME) gene family is expanded. It is actively expressed in cancers, but normally is testis-specific, possibly involved in spermatogenesis. The PRAME family has 26 members on human chromosome 1. In the macaque, it has eight, and has been very simple and stable for millions of years. The PRAME family arose in translocations in the common mouse-primate ancestor 85 million years ago, and is expanded on mouse chromosome 4. DNA microarrays are used in macaque research. For example,