Metabolic rate and thermoregulation in the Macedonian mouse Mus macedonlcus

The metabolic and thermoregulatory capacities of the Macedonian mouse (Mus macedonicus) of a population from a post-fire habitat on Mount Carmel, Israel, were studied. Post-fire habitats in the Mediterranean ecosystem of Mount Carmel are invaded by species that exist in the forest margins, including M. macedonicus, which established the largest mice population at early stages of recovery. Therefore, it was of great interest to study its thermoregulatory physiology. Mice were acclimated to a photoperiod of 12L:12D at an ambient temperature of 27 °C. The aim of this study was to reveal the physiological capacities of M. macedonicus that enable its invasion into the exposed, dry and hot post-fire habitats on Mount Carmel at the early stages of recovery. The results of our study show that M. macedonicus has a relatively low metabolic rate, which is also reflected in its relatively low food and energy consumption. Its thermoneutral zone is 32-37 °C, with a high lower critical point, similar to desert-adapted rodent species. This species has a relatively high overall thermal conductance 0.295±0.04 ml O₂·g^-1·h^-1·°C ^-1. However, its non-shivering thermogenesis capacity is within the range of other rodent species of a mesic origin, such as wood-mice. These physiological adaptations can partly explain its ability to cope with the challenges of post-fire habitats.