Question

The mammals from colder climates generally have shorter hair and not fully developed ears, eyes and other phenotypic characters. This is known as

Answer 1

Joel Asaph Allen formulated the Allen rule that states that animals in the colder regions have smaller extremities like ears, tails, limbs etc. It especially states that the body surface area to volume ratio in endotherms varies with the temperature of the environment. Animals living in cold climates will have a low surface area to volume ratio which means that the body surface area will be less. This ensures that heat does not dissipate much from these animals helping them to retain heat. Animals in warmer environments will have a larger body surface helping it to lose heat faster, ensuring that they remain cool.