A frog's gallbladder stores bile. The frog's gallbladder is a small green sac located under the liver and can be hard to find during dissection.
The most important digestive organ in a frog is the small intestines. Frogs have internal nares, which help them breath while their mouths are shut. Only male frogs have vocal sacs which can expand to call for their mate. Their two types of teeth are called the maxillary and vomerine, and both help insure prey doesn't escape.
There are over 4,000 species of frogs. In the United States, there are about 90 different species, and they can be found anywhere in the world except Antarctica. The smallest type of frog in the world is tinier than a dime. The largest type weighs more than 7 pounds and grows to be more than a foot long. Unlike humans, frogs absorb water through their skin.
Since the 1970s, a fungus called Chytrid has been the cause of over 100 species of frogs and other amphibians becoming extinct. This fungus has been detected in over 36 countries and affected about 285 different species including frogs. The Chytrid fungus is recognized as one of the biggest threats to amphibian life throughout the world.