North American Bullfrog (Rana catesbeiana

Question
Hello there Jedediah,

I am curious to know if the male American Bull frog is bigger or the Female American bull frog is bigger? Which one of them is bigger than the other?

I asked this because i tried searching for the answer online but different websites give me different answers.

These are some results i found.

"Males are larger than females."
from: http://www.beardsleyzoo.org/teachers-parents/animal.asp?mc_id=100

"Bullfrogs get to be about 6 inches long and weigh approximately 2 ounces. The male is bigger then the female."
from: http://www.learningtreasures.com/animal_antics_a.htm

However some sites mentions that females are larger.

"Bullfrogs could weigh up to one and a half pounds. Females, of course, are larger than their male counterparts."
from: http://frogworld.net/american-bullfrog/

I really have no idea which of them is bigger although i have been taught that in frog species, Females are often bigger but knew that American Bullfrog is an exception.

So please tell me which one of them is bigger.

Thanks.

Leonardo Heng

Answer
Dear Leonardo,
thank you for your question.
American bullfrogs are not an exepction of the rule, the females grow bigger than the males, although individual males may get very big and equal in size to females. The difference in size is also not as obvious as it is with many other species. To determine the sex of an American bullfrog, it's much more reliable to take a look at the eardrum, it's larger than the eye if the frog is a male.
I hope I was of some help to you
Jennifer