Frogs

Introduction:
Frogs are amphibians - meaning that they live part of their life in water and the other part of it on land. Adult frogs are characterized by long hind legs, a short body, webbed digits, protruding eyes and the absence of a tail. Skin texture varies: it can be smooth, warty or folded. Frogs have three eyelid membranes: one is transparent to protect the eyes underwater, and two vary from translucent to opaque.

Location:
The greatest diversity of frogs live in tropical regions, however they can be found almost anywhere except the Antarctic and on many oceanic islands. Frogs usually live in water or near places that have water like ponds and streams. However, some species will never enter the water, like frogs that live in trees and ones that burrow. Consisting of more than 5,000 species described, they are among the most diverse groups of vertebrates.

Size:
The largest frog is the giant or Goliath frog of West Central Africa. It can grow up to more than 1 ft long (30 cm). The smallest is the Cuban Pygmy frog, which is about 0.5" long (1.3 cm). The largest frog in America is the Bullfrog. It can grow up to more than 6" long.

Food:
Adult frogs eat many insects including flies, mosquitoes and other harmful insects. They also eat small fish, worms, snails and spiders.

Life Cycle:
Once adult frogs reach maturity, they will assemble at a water source such as a pond or stream to breed. Many frogs return to the bodies of water where they were born, often resulting in annual migrations involving thousands of frogs. The life cycle of a frog starts with an egg. A female generally lays frog spawn, or egg masses containing thousands of eggs, in water. A male will fertilize the eggs that then swell and develop a protective coating. The eggs are typically brown or black, with a clear, gelatin-like covering. Depending on the species and water temperature, the eggs will normally hatch within 3 - 25 days. Young frogs are called tadpoles or polliwogs. They look like little fish with a tail and external gills, which they breathe through. Tadpoles eat plants and decaying animal matter. As the tadpole develops, it will first grow the hind legs and then the front legs or arms. The tail slowly retracts and disappears and the frog hops up to the land as an adult. Not all eggs or tadpoles will make it to the adult stage. There are many threats like ducks, fish, insects and other water creatures eating the eggs, or the pond, they reside in, drying up. How fast tadpoles turn into an adult depend on the species and their natural surrounding. It might take a less than 2 weeks or up to a few months. The life span of a frog can also vary dramatically depending on the species, but the average is believed to be somewhere between 4 - 15 years.

Interesting Facts:
· The earliest known frog appeared about 250 million years ago.
· Frogs are most noticeable by their call, which can be widely heard during the night or day, mainly during their mating season.
· Camouflage is a common defensive mechanism in frogs.
· Many frogs contain mild toxins that make them distasteful to potential predators.
· In continental Europe, a large proportion of migrating frogs used to die on roads, before special fences and tunnels were built for them.
· The call of a frog is unique to its species.
· Some frogs have the ability to change colour.
· Most frogs have teeth used to hold prey and keep it in place until they can get a good grip on it and swallow their meal.
· Frogs that live in cold winter places, hibernate during this time.

Population:
Frog populations have declined dramatically since the 1950's: more than one third of species are believed to be threatened with extinction and more than 120 species are suspected to be extinct since the 1980's. Among these species are the golden toad of Costa Rica and the Gastric-brooding frogs of Australia. A Canadian study conducted in 2006 proposed heavy traffic near frog habitats as a large threat to frog populations. Habitat loss is a significant cause of frog population decline, as are pollutants, climate change, the introduction of non-indigenous predators/competitors, and emerging infectious diseases. Many environmental scientists believe that amphibians, including frogs, are excellent biological indicators of broader ecosystem health because of their intermediate position in food webs, permeable skins, and typically biphasic life. Frogs are an important part of the eco-system, which means that whatever happens to them, will affect other animals and even us in different ways. We are all connected in the web of life.

Help Protect Their Environment:
· Build a pond in your backyard for neighbourhood frogs.
· Help reduce the demand for unsustainable rainforest products by being careful about what you buy. Remember that our own lifestyle choices have an impact on tropical habitats.
· Make a donation to one of the various Wildlife Conservation groups to adopt an acre of endangered forest and help conserve amphibian populations.