These are the largest South American monkeys. Attenborough tells us this is the loudest sound made by any mammal and can be heard over a distance of 5 km. Howlers weigh 20 times as much as squirrel monkey. Among primates there is a tendency for some species to increase in size over time. Despite their size, howlers live in the treetops and feed among the thin upper branches.
Howlers select the fruit they eat by color as well as scent.
Unlike lemurs, monkeys have color vision and use color in their body language. Attenborough says they are the most vividly colored of the mammals. Next we travel to Africa and note one important difference between South American and African monkeys. Many African species are terrestrial. Vervet These monkeys are seen foraging over grasslands.