Currently worldwide it is estimated that there are over 7,000 species of amphibians belonging to three distinct groups; Frogs (includes toads), Salamanders, and Caecilians (legless amphibians not found in the US). They come in all sizes from the world's smallest known vertebrate called the little land frog (Paedophryne amanuensis) the size of a housefly at an average of 7.7 millimeters long found in Papua New Guinea.
The largest amphibian is the Chinese giant salamander (Andrias davidianus) reaching a length of 180 cm (5.9 ft).
From green, brown, blue, red, spotted, stripped, camouflage, smooth and bumpy their diversity is astounding.
Tomato Frog From Madagascar
Fire Salamander From Europe
Blue Poison Dart Frog From Suriname and Brazil
The word amphibian translates into double life where the larvae go through an amazing transformation or metamorphosis. While the classic egg, tadpole, adult life cycle that has been taught in just about every grade school in America, some amphibians have very different and unique life cycles. The now extinct gastric breeding frogs incubated prejuvinile stages of their offspring in the female’s stomach. Marsupial frogs develop in a pouch of the adults’ females back and Surinam tads develop directly in the female’s skin on the back. Within Cleveland Metroparks the most abundant vertebrate is the redback salamander. This lungless amphibian spends most of their life under logs on the forest floor never entering water to lay their eggs like other amphibians. They will lay a clutch of 6-10 eggs under a log where they will tend them until they hatch into little miniature adults in late summer. This demonstrates that nature does not stick to the rules and that there numerous exceptions to the classic life cycle.
While this is fascinating, amphibians have developed other adaptations that are even more amazing. Several frog species like the wood frog, spring peeper and grey tree frog, can enter a frozen state for days or even weeks. The wood frog, the most northern species in North America is the champion of this adaptation. Check out this video explaining and demonstrating the process. http://www.youtube.com/watch?v=dhUF5I6wr2A
Amphibians are charismatic and beautiful animals, but their role in ecosystem in often underappreciated. We know that they eat insects and this is important in controlling prey populations, but often they are less selective than we may believe. Bull frogs will eat anything that can fit into their mouth including other bull frogs. http://www.youtube.com/watch?v=dhUF5I6wr2A
Amphibians in turn are food for snakes, birds, mammals, insects and even other amphibians. However, one of their most important ecological roles they provided is the cycling of nutrients in an ecosystem. Amphibians are eating machines and their food is quickly digested and excreted as waste and then is available for plants and other organisms to utilize. Even tadpoles as they graze on algae in vernal pools are releasing valuable nutrients for the other plants and animals in the wetlands.
Cleveland Metroparks is home to 24 species of amphibians. http://www.clevelandmetroparks.com/Uploads/Public/Documents/brochures/REPTILR_FINAL.pdf
Some are very common and widespread like the American toad or the green frog, while others ore only found in specific habitat or region. Cleveland Metroparks is located in a unique geographical region with the Cuyahoga River splitting the county in half. Heading east you are entering the beginning of the Appalachian Plateau. Heading west the terrain flattens as this is the beginning of the Great Plains. This geologic separation results in changes of local amphibian populations. In the East pickerel frogs are more common finding refuge in the abundant cool ravines. In the west leopard frogs are found where they prefer shallow grassy ponds, and in the north eastern reservations is the only location to find mountain dusky salamanders on the very western edge of their range.
While they are diverse and often abundant, this class of animals is currently one of the most threatened. Species extinction is greater now than it has been since the dinosaurs went extinct. Habitat protection is vital! Decisions we make everyday can make this world a little more amphibian friendly. As Kermit the frog says “It's not easy being green” https://www.youtube.com/watch?v=rRZ-IxZ46ng but we owe it to ourselves and Kermit to try our best.