[ ăl′ənz ]
The principle holding that in a warm-blooded animal species having distinct geographic populations, the limbs, ears, and other appendages of the animals living in cold climates tend to be shorter than in animals of the same species living in warm climates. Shorter and more compact body parts have less surface area than elongated ones and thus radiate less body heat. Allen's rule is named for the American zoologist Joel Allen (1838-1921). Compare Bergmann's rule.
CAN YOU FEEL THE WEAL WITH THIS WORD OF THE DAY QUIZ?
Did you collect all of last week’s words, but eftsoons forget what they mean? Don’t worry, we’re here to jog your memory. See how many words from the week of May 18 to 24 you can get right!
Question 1 of 7
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.