When, and When Not to Leave

Abstract

The tropics are very seasonal. There are times of year when the carnivores are more numerous, when there is more sun, when food is more scarce, when there is more rain. Many tropical plants and animals sit tight and tough out the hard times·by being unreproductive or dormant. But many tropical animals get up and move to more hospitable localities when unfavorable seasons come along. Such local seasonal movements have long been apparent to tropical field naturalists and rural residents. In a tropical dry forest, for example, many butterflies, bugs, beetles, lizards, monkeys and birds move into moist and semi-evergreen lowlands and riparian understory vegetation during the dry season. Then, when the rains come, the lowland forest understory becomes a shadow desert and the animals move back onto the sunny hillsides where the food is. But we have long been oblivious to a much more dramatic kind of movement in the tropics.