The skin is rich in pigment cells, which provide effective means of camouflage, and the chameleon is a well-known example.

They include the orangutan, the gibbon, the chimpanzee and the primate with whom Attenborough has arguably his most famous encounter, the mountain gorilla.

Not only are there many major categories of creatures – monkeys, rodents, spiders, hummingbirds, butterflies – but most of those types exist in many different forms. Even so, very few of these perished in the exact physical and chemical conditions necessary for fossilisation. Although the magnolia, for instance, contains male and female cells, pollination from another plant is preferable as it ensures greater variation and thus evolution. This was problematical for some hunters, such as spiders and scorpions, who developed courtship rituals to ensure that the female didn't eat the male. By the time he reaches the Colorado River bed, the geological strata are 2,000 million years old—yet there are no fossils.

To celebrate the 40th anniversary of the book's first publication, David Attenborough revisited Life on Earth, completely updating and adding to the original text, taking account of modern scientific discoveries from around the globe. It then evolved shielded tentacles and the casings eventually enveloped the entire body: these creatures are the brachiopods. Highly acclaimed as a milestone in the history of British wildlife television, it established Attenborough as not only the foremost television naturalist, but also an iconic figure in British cultural life. Insect eaters vary enormously from the aardvark, giant anteater and pangolin to those to which much of this programme is devoted: the bats, of which there are nearly 1,000 different species.Such new insights will be described in this new edition in their appropriate places in the pages that follow. The land is so dry that only isolated juniper trees and low scrub freckle the surface of the cliffs, and the rock strata, some soft, some hard, are clear and stark. All these advances in knowledge and many more will be mentioned in the appropriate places in the text that follows. Today, however, it is possible to establish genetic identity of a species in a few hours using a piece of apparatus no bigger than a mobile phone. Billion Years in 12 Chapters is an enlightening story of survival, of persistence, illuminating the delicate balance within which life has always existed, and continues to exist today.

These represent times when the land rose, the seas drained away and the seabed became dry so that the deposits that had accumulated on it were eroded away.The others were supplanted by the monkeys and a primitive species that still exists is the smallest, the marmoset. Of those that did, only a tiny proportion happen to lie in the rocks that outcrop on the surface of the ground today; and of these few, most will be eroded away and destroyed before they are discovered by fossil hunters.