VIDEO: Bullfrogs Eating Each Other

As gross as they may be, frogs are also fascinating – the american bullfrog in particular.

These frogs eat birds, spiders, scorpions and, sometimes, each other.

According to Wikipedia, the American bullfrog is an amphibious frog, a member of the family Ranidae, or “true frogs”. This frog has an olive green back and sides blotched with brownish markings and a whitish belly spotted with yellow or grey. The upper lip is often bright green and males have yellow throats.

It inhabits large, permanent water bodies, such as swamps, ponds, and lakes, where it is usually found along the water’s edge. The male bullfrog defends a territory during the breeding season. His call is reminiscent of the roar of a bull, which gives the frog its common name.

This frog is native to southern and eastern parts of the United States and Canada, but has been widely introduced across other parts of North, Central and South America, Western Europe, and parts of Asia, and in some areas is regarded as an invasive species.

The bullfrog is harvested for use as food in North America and in several countries into which it has been introduced. It is also cultured in controlled environments, though this is a difficult and not always successful undertaking. Some international trade in frog legs occurs for human consumption.

To establish social dominance within choruses, bullfrogs demonstrate various forms of aggression, especially through visual displays. Posture is a key factor in establishing social position and threatening challengers. Territorial males have inflated postures while nonterritorial males remain in the water with only their heads showing.

For dominant males, their elevated posture reveals their yellow-colored throats. When two dominant males encounter each other, they engage in a wrestling bout. The males have their venters clasped, each individual in an erect position rising to well above water level.

The New Jersey study noted the males would approach each other to within a few centimeters and then tilt back their heads, displaying their brilliantly colored gular sacs. The gular is dichromatic in bullfrogs, with dominant and fitter males displaying yellow gulars.

The New Jersey study also reported low posture with only the head exposed above the water surface was typical of subordinate, or nonterritorial males, and females. High posture was demonstrated by territorial males, which floated on the surface of the water with their lungs inflated, displaying their yellow gulars.

Males optimize their reproductive fitness in a number of ways.

Early arrival at the breeding site, prolonged breeding with continuous sexual activity throughout the season, ownership of a centrally located territory within the chorus, and successful movement between the dynamically changing choruses are all common ways for males to maintain dominant, or territorial, status within the chorus.

Older males have greater success in all of these areas than younger males. Some of the males display a more inferior role, termed by many researchers as the silent male status.

These silent males adopt a submissive posture, sit near resident males and make no attempt to displace them. The silent males do not attempt to intercept females but are waiting for the territories to become vacant.