Frog bones. Some are like human bones. That is they have a skull, backbone, vertebrae, digits, pelvis bone. Frogs are vertebrates and their skeleton is internal. What the different is about a frog skeleton compared to a human’s is, the frog’s is made for the jump. The bones are lightweight, just like birds have lightweight bones for flying. Their backbone connects to their skull by bony protrusions, condyles. These only allow side to side movement of the head. Their vertebrae are connected to little to no ribs. Ribs are fragile and the impact of many landings would create a lot of stress. The vertebrae are usually eight maximum in existing species and they connect to the sacral vertebra. The tail bones have fused by the time the frog is an adult. Then, special to frogs is a movable joint. This is one of their secrets to those incredible jumps. The joint allows the sliding of the pelvis along the backbone. The hip joint allows the movement needed for the jump in the hindlimbs, the legs. Now we come to the leg bones which are elongated, even the hip bone, and the ankle bones, allowing added leverage. The forelimbs, the arms, are shorter but with the shoulders they create the shocks, like in cars, they absorb the impact during landing. These limbs even allow for walking, the frog’s locomotion isn’t exclusive to jumping you know. Let’s not forget the digits. The hands have four, only the pinky is missing. Of course, there are exceptions to everything. And the feet have four or five toes, depending on the species.
What about teeth you say? Well frogs do have teeth, but their purpose is for holding onto food for swallowing. Food is likely to be swallowed whole, when it comes to frogs. The teeth mostly reside in the upper jaw. Only some frogs have these pointy protrusions in the lower jaw and only one species has real lower jaw teeth. Some may not have teeth at all. For those with teeth, the vomerine teeth are particularly useful. They are added rows of teeth in the upper jaw. Frog teeth go through a lot of wear-and-tear, that’s why they need to be replaced every so often throughout the frog’s lifetime.
Works Cited:
Behler, J. L., & Behler, D. A. (2005). Frogs: A chorus of colors. New York, NY: Sterling Publishing Co., Inc.
Beltz, E. (2005). Frogs: inside their remarkable world. Buffalo, NY: Firefly Books Ltd.
Forsyth, A. (2008). Nature of the rainforest: Costa Rica and beyond. Ithaca, New York: Cornell University
Press.
Photo credit: Ronald T. Richards/NBII.Gov
(above)
Photo taken by Ellen Pitre
Frog
February 13, 2009
(below)
