Question

Which of the following explains Allen’s rule?

• A. The presence of CAM pathway
• B. The presence of blubber in aquatic mammals
• C. Shorter ears and limbs in mammals living in colder regions
• D. The huddling together of large groups of penguins to stay warm

Answer 1

The correct option is C Shorter ears and limbs in mammals living in colder regions

The rule says that the body shapes and proportions of endotherms vary by climatic temperature by either minimizing exposed surface area to minimize heat loss in cold climates or maximizing exposed surface area to maximize heat loss in hot climates. Thus the rule predicts that endotherms from hot climates usually have ears, tails, limbs, snouts, etc. that are long and thin, whereas equivalent endotherms from cold climates usually have shorter and thicker versions of those body parts.