Howler monkeys are a noisy bunch, and their deep hollering vocalizations (which seem to be associated with small testicles) can travel remarkable distances through the canopy. New research published in the journal Animal Behaviour has uncovered another way in which these roaring monkeys are perfectly adapted to rainforest life, as they found that howlers have remarkable navigation skills. Not only could they remember the location of their favourite foods (and when they were in season) they knew the critical locations for reminding neighboring troops to keep out of their territory with warning calls. The research, led by Oxford Brookes University, studied black howler monkeys (