Frogs around the World
By Alexandra Manoni and Chris Hover
There are approximately 4,74o species of frogs around the world. Although only about 90 species are present in the United States. Since 1800, 120 species of amphibians (including frogs, toads, and salamanders) have disappeared. This devastating rate of extinction is something we can help to prevent.
The map below shows the areas where amphibians like frogs thrive, and where they do not exist at all. In warm, tropical, climates, frogs are more common. There is a dense population of frogs in areas close to the equator, however they do not exist in desert climates, regardless of whether or not the desert is on the equator. Frogs also don't live in freezing, ice-covered areas like Antarctica. The map below shows the general location of frogs and the population density in that area.
Frogs in the Ecosystem
Because, frogs are known as indicator species, they can give scientists valuable information on how an ecosystem is currently functioning. They are predators and prey, so many animals are affected by them. Since this is the case, frogs provide insight into the health of the ecosystem. A frog's diet mainly consists of insects and small animals like earthworms, minnows and spiders.
The life cycle of a frog begins when an adult frog lays eggs in a pond or stream. When these embryos hatch, they become tadpoles that gradually grow in length. They swim by moving the bottom half of their body in quick, sharp, movements, until their front legs break through. It is at this point in time where they are able to begin pulmonary breathing, or breathing above water. They surface as tadpole frogs, since the end bit of their original tail is still present. Over time, this last sign of being a tadpole disappears, and they become adult frogs, ready to lay eggs. When they lay their eggs, the life cycle of a frog is complete.
This video shows tadpoles hatching from eggs laid by an adult frog. It marks the beginning of a frog's life cycle.
All around the world, there is a beautiful variety of frogs in different patterns and colors. From bright vivid, colors in the most tropical of areas, to more neutral earth-tones in the northeast, frogs adapt to their environment by blending in with the colors of their surroundings.
Frogs have a wide variety of predators. These range from snakes, lizards, and birds, to various small animals like hedgehogs. Frogs can never be safe from predators, even underwater. Sharp toothed fish and mammals known as water shrews hunt them when they are in their aquatic environment. To top it all of, some frogs have to worry about being eaten by other hungry frogs! Because of all of their predators, frogs have adapted and developed many techniques to protect themselves. The only predator that they don't have skills to fight off is perhaps the most dangerous of them all: pollution. It was recently discovered that the population of frogs worldwide is in decline, and this is believed to be due to an increase in pollutants in their environment.