The frog is a cold-blooded freshwater amphibian. It has smooth moist skin and powerful back legs for swimming and hopping up to 5 meters!
Concealed under a stone, The North American wood frog is no longer breathing, its blood is no longer flowing through its veins and two-thirds of the water in its body is frozen. Much like a little factory, its body has started to produce substances that will allow it to survive being frozen for several weeks: sugar that supplies energy to its dormant organs and a special antifreeze that prevents ice from forming inside its cells.
Most of the 3,500 species of frogs and toads mate in water. Male frogs hold the female in a position known as the amplexus. But rather than bothering the female, this tender hug causes her to fill the water with hundreds and hundreds of eggs, which the male then does his best fertilize. The future parents do not emerge from their embrace until the fertilization of the eggs is complete.
After fertilization, the eggs become tadpoles, aquatic larvae breathing through gills, and then adult frogs. Each stage usually last several weeks, but can also last up to two years in some species.
Certain Indonesian frogs have webbed feet and a layer of skin that extends from the last digit to the elbow joint on each of its front limbs. This set of membranes works just like a small parachute.
Small dendrobates are not only the most colorful frogs in the world, they are also the most poisonous. The venom produced by their skin glands is so powerful that the Indians of the Amazon smeared it on the points of the lances and arrows they used for protection and for hunting small game. The venom from just one of these frogs is said to be enough to coat the heads of 50 arrows!