small mammal versus large mammal with body temperature?

Question

why would it be more difficult for a small mammal to be active during the day and allow its body temperature to fluctuate than a large mammal such as camel??

Answer 1

The larger your surface area to mass ratio, the harder it is to maintain a constant body temperature. The greater the amount of surface area, the larger the amount of heat transfer (in either direction).

Small mammals have much larger surface area to mass ratios than large mammals, thus have a more difficult time maintaining body temperature in either cold or hot conditions.

Of course, you can fix some of that with adaptations like insulating coats.

Answer 2

The honor of being the world's smallest mammal goes to Thailand's bumblebee bat. The bumblebee bat weighs less than a penny and full grown is about 11 mm in length. Some of you creature savvy people out there may think the world's smallest mammal is the Etruscan pygmy shrew and you may have a case. The debate is whether mass or size constitutes the smallest and although lighter, the pygmy shrew is longer.

Answer 3

More mass, more temperature inertia.

Also a big animal has a much lower corporeal temperature than smaller animals. The exceptions are horses with unusually high temp and dogs with more or less the human temp so a bit too low for their mass.