Horses , lions and dogs are quadrupeds , but humans are bipeds .

马、狮子和狗是四足动物，但人是二足动物。

It is now generally accepted that the earliest bipeds lived in wooded , even forested habitats .

在如今，连早期两足动物生活在树木繁茂甚至草木丛生的栖息地，这样一种看法都得到了广泛接受。