The more 'ribbids' the better for Kermit

Author: John Monczunski

If they want to be the biggest frog on a pond’s lily pad, male frogs need to speak up. Lady frogs prefer “talkative” males, according to Sunny Boyd, Notre Dame professor of biological sciences. It seems the ladies judge Kermit on the basis of his vocal talents, with the more pulses and the longer the call equaling the more desirable male. Girl frogs aren’t interested in the strong silent type; the studs are the guys belting out the long “ribbids.”

“Females choose the longer-call males because it’s an energetically costly behavior that correlates with a more fit male, and that translates into producing more fit tadpoles,” Boyd says.

For the ND biologist, whose work focuses on understanding behavior down to its most basic level, the biochemical pathways that regulate the action are the most intriguing thing about the frog call. In particular Boyd has studied the role of arginine vasotocin (AVT), a chemical produced in the frog brain that plays a variety of roles in frog behavior, including mating call conduct. Among other things, AVT has been shown to increase mate call frequency in male frogs and to increase female attraction to males.

In her study of what controls behavior, Boyd also looks at how individual cells communicate by analyzing the production of particular chemical messengers in the brain. She also is researching how individual parts of the brain contribute to behavior and is attempting to understand interactions of animals in the field.

John Monczunsk is an associate editor of this magazine. Email him at