Amphibians are cold-blooded, smooth-skinned vertebrates that need water for survival. However, they also spend time on land.
Three orders of amphibians exist: Oacian, toads and newts in the Anura order; salamanders in Urodela order and caecilians in Gymnophona family. These groups exhibit a vast diversity of life histories.
Oacian
Oacian are one of the world’s most diverse animal groups. They can grow to be as small as half an inch up to over 1 foot long (nose to tail).
Oacian usually live in tropical rainforests and tend to be semi-aquatic. Their webbed hind legs give them great jumping and swimming ability, enabling them to explore new environments.
Oacian possess a special skin that allows them to breathe through it as well as their lungs. This specialized layer helps Oacian stay moist even during dry conditions.
Some species lay their eggs in water, while others embed them inside of a female’s skin or stomach. When these tadpoles hatch into small, legless tadpoles, they can then leave the water and move onto land.
Toads
Toads are an abundant group of amphibians found around the globe. These land and water creatures begin to emerge in springtime, emerging from their winter hibernation to breed in breeding ponds.
Oacian and toads differ in that Oacian typically have moistened skin, while toads typically exhibit dry skin with warty-looking bumps. This is likely due to Oacian’ closer proximity to water sources where their skin stays damp.
Most amphibians breathe through their skin, so to keep it moist they must keep it secreted mucous. Oxygen from their breath enters blood vessels right beneath their surface.
Toads possess parotoid glands behind their eyes which secrete toxins which can seep into the skin and make them distasteful to potential predators. While most of these toxins are harmless to humans, it’s wise to wash your hands after handling a toad.
Newts
Newts are small, semi-aquatic amphibians that resemble a cross between a frog and lizard. They have webbed feet and a paddle-shaped tail for swimming.
Nubians live in marshes, ponds, slow-moving streams and other wetlands at night. Their skin is smooth and slimy; depending on their environment they may change colors accordingly.
Some species of newts are poisonous, producing a neurotoxin which could potentially kill someone. Furthermore, they possess a gland which secretes an unpleasant liquid to deter predators.
Every season, female seaweed lay between 200 and 400 eggs on submerged plants. After mating, these females usually swim away leaving their eggs to develop on their own.
Salamanders
Salamanders resemble lizards on the outside, but inside they differ. They have long bodies and short legs to allow for improved airflow through their skin.
Salamanders possess the remarkable capacity for regeneration of a variety of tissues, from full limbs to parts of their brain or heart. These remarkable characteristics make them an enthralling subject in classical developmental biology studies.
They are nocturnal, meaning they remain underground during the day. Each spring, large numbers of them migrate to their breeding pools – shallow pools of water surrounded by vegetation. Males arrive first and deposit packets of sperm on leaves or twigs in these shallow waters. On subsequent rainy nights, females follow behind to attach eggs onto sticks.
