Cebids include widespread and common species, as well as species that are rare or have restricted ranges. Cebid species populations are probably most profoundly affected by habitat destruction, although many species are also affected by research and pet trade markets and by hunting. A subspecies of Cebus apella (C. apella robustus) is listed as endangered by the IUCN. Cebus xanthosternos and Cebus kaapori are listed as critically endangered. Captive breeding programs are underway for these species. Two subspecies of Saimiri oerstedii are at risk: S. o. oerstedii is considered endangered and S. o. citrinellus is considered critically endangered. Saimiri vanzolinii is listed as vulnerable. Leontopithecus caissara is considered one of the 25 most endangered primate species worldwide, it is listed as critically endangered. All other Leontopithecus species are endangered. Other endangered marmosets and tamarins are: Callithrix flaviceps, Saguinus bicolor, and Saguinus leucopus. Saguinus oedipus is critically endangered.