Environmental and Genetic Influences on Growth of the Wild Rabbit, Oryctolagus-Cuniculus (L) in Australia

Abstract

Environmental variation caused more variation in the growth rates of wild rabbits than did genetic divergence among populations in three climatic regions in Australia. The growth of various parts of the body responded to different environmental influences. Growth of the body core of kittens varied with the number of littermates. Growth of the pes varied with ambient temperature and the number of littermates. Growth of the pinnae, organs with special thermoregulatory function, was affected markedly by ambient temperature. Growth rates in regional rabbit populations differed consistently in two generations, manifesting differences in physiology and possible genetic divergence. Sub-alpine rabbits grew faster in body length and head length than did rabbits of mediterranean and arid climates. The extremities of mediterranean rabbits grew slower than those of arid and sub-alpine rabbits. The regional variation in growth physiology was determined either by persisting influence of the field environments transmitted maternally through two generations, or by genetic divergence of populations since the few progenitors were introduced to Australia 125 years previously.