高中三年级英语(人教版)全一册 Unit 14 Integrating Skills

　　PRIMATES

　　Like all other living creatures, human beings belong to a group of other animals that share certain characteristics. Zoologists place us in a group called primates, which include other mammals such as apes and monkeys. Among the key features found in primates are hands and feet that can grasp and often have opposable thumbs and toes. That means that primates are better than other animals at holding, moving and using objects. Indeed, many primates, most notably human beings, have learnt to make and use tools. Primates also have a better sense of touch and the primate brain is larger -- compared to body size -- than that of other animals. Depending on the size of the brain, primates are divided into two groups: higher primates (human beings and apes) and lower primates.

　　There are some 183 species of primates and they are also sometimes divided into two other groups: new world primates, which are small monkeys that live in trees, such as the spider monkey and the night monkey; old world primates include monkeys, apes and humans. They are bigger and spend more time on the ground.