ABSTRACT Monitoring the abundance of widely distributed animals poses many logistic challenges, and is rarely done because the wide distribution generally suggests a lack of conservation concern and thus funding. However, as there are increasing concerns about the conservation status of some widely distributed primates, evidence based management requires estimates of abundance. In this paper we review how such estimates can be done and have been done for some animals. We also explore in depth the one attempt to do so for a primate, the long‐tailed macaque. We identify weaknesses in the work that has been done and suggest how a reliable estimate could be obtained.