In recent years, a small revolution has occurred in the study of
animal foraging patterns. Various new ways have emerged to track
and record the movement of animals over relatively long periods
and computer scientists have developed models that do a good job
of reproducing this behaviour for many living things. The
curious thing is that these models are largely based on random
walks. In these simulations, an entity’s next move is almost
entirely independent of all its previous moves. Memory is of
little or no significance to these creatures. These models work
well for inanimate processes such as Brownian motion and the
movement of bank notes but also capture the behaviour of
zooplankton, marine predators and even spider monkeys. That’s
surprising because many animals have developed good memories
that allow them to perform sophisticated cost-benefit analyses:
should I revisit the fruit tree I raided last week or spend time
and energy looking for a new one? It’s easy to imagine that a
good memory would confer s