The North American Bullfrog (Rana catesbeiana), is an aquatic frog, a member of the family Ranidae, or “true frogs”, native to much of North America.
The bullfrog is a large species in the family Ranidae; it can grow to a length of 9–15 cm (6 inches) with a weight of up to 500 g (one pound), the largest frog in North America. Females are typically larger than males. They are generally varying shades of green or brown, with dark brown, dark green, or black blotching and a yellow or white underside.
The skeleton of an adult frog consists of bone, hyaline cartilage, and calcified cartilage. The calcified cartilage can be found throughout the body of the frog, but it is particularly more noticeable in the epiphyses of the long bones in the limbs and shoulder-gridle. The frog has no scapula and a suprascapula which allows for greater range of motion for long jumps. The radius and ulna have become fused into a single bone, the radio-ulna, and the tibia and fibula have become fused into a single bone, the tibio-fibula.
The vertebrae comprise ten bones; nine are true vertebrae, and the rod-shaped urostyle that is almost as long as the other nine. The head of the frog is flat but its form depends on the extensive separation of the jaw bones; the orbital cavities and the horizontal direction of their floor also have an effect on the form of the head. The central nervous system is made up of the spinal cord and the brain, where the spinal cord is a bit smaller than the brain. The peripheral nervous system contains the cranial nerves and spinal nerves.
They have four legs, not two hands and two legs as commonly misconceived. Front feet and back feet are both webbed.
You can tell the sex of a bullfrog by comparing the diameter of the eye with the ear drum (Tympanum) If the tympanum is much larger than the eye, it’s a male.
If it’s the same size or a bit smaller it is a female.
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This bubble taken in the same pond as the bull frog. If you look closely, you can see the face of a bullfrog in the bubble: