Northern muriqui  (Brachyteles hypoxanthus)

The muriqui, or woolly spider monkey, is the largest New World primate, and in the late 1980s was recognised as two distinct species: the northern muriqui (Brachyteles hypoxanthus) and the southern muriqui (B. arachnoides) (4). The main difference between the northern and the southern muriqui is the presence of a small thumb in the northern variety (2). Otherwise, however, they are almost identical in appearance. Muriquis have long limbs and a long prehensile tail, allowing them to be particularly agile amongst the trees (5). The thick coat is greyish-brown in colour and males may have a more yellow tinge (5) (6).