My method to determine the bullfrog sex

[Allen]

Hey guys,I don't know how do you guys determine the GABF sex.I happen to see a thread asking for help to determine the GABF sex,and I would like to share my experience on it.
(Thanks for John Clare's picture,and sorry for my poor scrawl)
I think the male GABF's head length accounts for about 1/3 of the whole snout-to-vent length,but the female is about 1/4,as you can see from the pictures below.
https://www.facebook.com/photo.php?f...type=1&theater
https://www.facebook.com/photo.php?f...type=1&theater