Home range of desert mule deer: Testing the body-size and habitat-productivity hypotheses

The body-size hypothesis of home range predicts that, given constant home r ange productivity larger animals with higher absolute metabolic requirement s use larger home ranges to meet their metabolic needs. This relationship i s well supported across a wide range of mammals and often has been invoked to explain differences in home range size between series that differ in bod y size. However, the body-size hypothesis has rarely been tested within a s pecies. A corollary to this hypothesis states that for a given mass, animal s in areas of low habitat productivity should have home ranges larger th;ln those in productive habitat. To test these 2 hypotheses, we radiomonitored desert mule deer (Odocoileus hemionus crooki) for 2 years in southwest Tex as to determine the effects of ses. mass, and habitat productivity on annua l home range size. Although male mule deer had more massive bodies than fem ales (P < 0.001) and used consistently larger annual home ranges than femal es (P < 0.01), we found Little support for the body-size hypothesis. In con trast, we found ses-specific support for the habitat-productivity hypothesi s. Male and female mule deer had home ranges of similar size in areas of hi gh habitat productivity but males used larger home ranges than females when habitat productivity; was low. Our results suggest that differential ses r esponses to productivity may be the mechanism underlying the frequent obser vation that male cervids have larger home ranges than female cervids.