Database Reference
In-Depth Information
13
Animal Movement
Stefano Focardi and Francesca Cagnacci
13.1 Introduction
13.1.1 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, dat-
ing 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. Occasional sallies outside the area, per-
haps exploratory in nature, should not be considered as in part of the home range.”
This definition does not contain a quantitative definition of home-range bound-
aries, but it implies that a home range is a well-identifiable area; one consequence
259
