Question

Very small animals are rarely found in polar regions because

• A. small animals have a larger surface area relative to their volume, so they lose body heat very fast when it is cold outside
• B. small animals have a smaller surface area relative to their volume, so they lose body heat very fast when it is cold outside
• C. small body volume makes internal heat production very difficult
• D. none of these

Answer 1

Answer: (A)

small animals have a larger surface area relative to their volume, so they lose body heat very fast when it is cold outside

Answer 2

Temperature affects the absolute size of an animal and the relative proportions of various body parts. Birds and mammals attain greater body size in cold regions than in warm areas. But poikilotherms are smaller in cold region. This is Bergmann's rule. This is true because small animals have larger surface area relative to their volume, so if they are in cold, they lose their body heat very fast. In cold climate, reduced surface area to volume ratio is ideal.