Introduction

Historical Overview

The curiosity of humans about animal movements dates back to ancient times and probably to prehistory. As a matter of fact, Aristotle (in. The History of Animals) described animal migrations. The capacity of animals to move with accuracy during long displacements was surprising and has been considered a mystery of nature till recent times. Much before the scientific foundation of diffusion due to the botanist Robert Brown in 1927, the roman poet Lucretius described in detail the motion of dust. For centuries, scholars hold Descartes' view that animals are thoughtless automata. Modern experimental research dates back to the end of nineteenth century, after the publication of The Origin of Species by Darwin in 1859. Researchers of that period adopted a subjective and anthropomorphic view of animal behavior and movements. Later, scholars started to interpret animal movement in a more objective, scientifically sound way, by investigating animal reactions to stimuli present in their environment, such as the gravitational field, the presence of light, gradient of humisdity, and so forth.

The concept that individual animals restrict their movements to finite areas known as home ranges is perhaps as old as ecology itself. Seton in 1909 observed that “No wild animal roams at random over the country; each has a home-region, even if it has not an actual home.” The definition of home range from Burt, dating back to 1943, is probably one of the most long lasting and widely used in ecology: “that area traversed by the individual in its normal activities of food gathering, mating and caring for young.