  Rapoport's rule claims that latitudinal ranges of plant and animal species
are generally smaller at low than at high latitudes. However, doubts as to the
generality of the rule have been expressed, because studies providing evidence
against the rule are more numerous than those in support of it. In groups for
which support has been provided, the trend of increasing latitudinal ranges
with latitude is restricted to or at least most distinct at high latitudes,
suggesting that the effect may be a local phenomenon, for example the result of
glaciations. Here we test the rule using two models, a simple one-dimensional
one with a fixed number of animals expanding in a northern or southerly
direction only, and the evolutionary/ecological Chowdhury model using birth,
ageing, death, mutation, speciation, prey-predator relations and food levels.
Simulations with both models gave results contradicting Rapoport's rule. In the
first, latitudinal ranges were roughly independent of latitude, in the second,
latitudinal ranges were greatest at low latitudes, as also shown empirically
for some well studied groups of animals.
