Effect of Temperature and Body Size on The Metabolic Rate of The Egyptian House Mice Mus Musculus and The Roof Rat Rattus Rattus

The metabolic rate of the different sized rodents in relation to external temperature was studied. These rodents are the house mice Mus musculus and the roof rat Rattus rattus inhabiting the houses and fields of Egypt. The results show that the mice Mus musculus of small size had a higher rate of oxygen consumption and higher heat production than the large size one Rattus rattus. Also, the data indicate that increase of external temperature resulted in a significant decrease of oxygen consumption in the two experimental species up to 30ºC, then a gradual increase in oxygen consumption takes place as temperature increases. However, the zone of thermal neutrality and basal metabolism lies around 30ºC. From the metabolic rates obtained at various ambient temperatures, a temperature- metabolism curve can be constructed in the two experimental species.