life with little sun. Whole populations of animals are now forced to travel great distances in pursuit of food and warmth. Three hundred thousand Baikal teal gather to escape from the Siberian winter by migrating south to Korea, the world’s entire population in a single flock. 

 

But there are parts of the world that have no seasons. In the tropics, the sun’s rays strike the earth head on and their strength is more or less constant all year round. That is why the jungle grows so vigorously and supports so much life. This forest covers only three percent of the planet’s surface but it contains more than fifty percent of all its plants and animals. The canopy is particularly rich. There are monkeys, birds and millions of species and insects, exactly how many we have no idea.