Salamander

Order Urodela

Amphibian

Transcript:

Today on Animal Fact Files we’re discussing salamanders. Salamanders are classified in an order that also includes newts. Technically speaking, all newts are salamanders but not all salamanders are newts– in fact most salamanders are not newts. To tell them apart, you need only look at their skin. Newts have lumpy, dry skin and non-newt salamanders have smooth, slimy skin. Of course, it's worth mentioning that there are over 600 salamander species, so there are some exceptions to that observation, but that will generally help you tell the two types apart.

Salamanders are separated from other amphibians because of how they look as well. These vertebrates are lizard-shaped, though they're not technically lizards because they're not reptiles. Like lizards, however, salamanders have a tail and limbs as adults which each other amphibian group lacks in some capacity. Frogs, which include toads, lack a tail as adults, and caecilians lack limbs– they kind of look like earthworms. It's worth mentioning, again, that the large number of salamanders in the world means there are exceptions, such as the siren that lacks hind limbs, but overall this is the salamander body structure.

Fascinatingly, salamanders are almost entirely restricted to the northern hemisphere. They can be found in the northern section of South America, but this is the only place they naturally occur below the equator. Some salamanders, such as the olm, are fully aquatic and never leave the water while others are entirely terrestrial meaning their young metamorphose entirely inside their protected eggs, however, generally speaking, salamanders spend their early life in water and their adult life on land. Still, they're amphibians, which means they require moisture in their environment to breathe. 

Salamanders breathe through their skin. They can absorb oxygen, as well as other elements, through the surface of their skin and into their body. This is why all amphibians are susceptible to polluted habitats. In fact, more than half of the living salamander species in the world don't even have lungs! Some species sport gills as adults, such as the axolotl, and these are used in respiration as well, much like a fish's gills! Axolotls are neotenic meaning they retain their juvenile characteristics into adulthood, many salamander adults, however, lose these external gills and leave the water to live the remainder of their life on land.

The largest living salamanders reach more than 5 feet (1.5 m) long, however most species are under a foot (30.5 cm) in length. They have teeth in both their upper and lower jaws even as juveniles, and these help catch prey such as fish, other amphibians, invertebrates, and even small mammals. Like frogs, terrestrial adult salamanders have a sticky tongue to hold onto prey as well! In turn, these animals are eaten by larger amphibians, reptiles, and fish, aquatic mammals, and birds. Many have slippery skin to help them escape, and those that do may live 5 to more than 15 years in the wild depending on the species.

If you've ever seen one of these amphibians walk, you know it's something sort of like how a fish swims, except it's on land! This is called "lateral undulation". Even with their goofy stride, salamander males show off their skills and colors for potential mates. The boys produce a sperm packet, called a spermatophore, that the girls pick up and take into their cloacal if they accept the advances. Now depending on the species she’ll lay her eggs on water or on land; the eggs may hatch in water with a fully aquatic juvenile stage or fully develop to adult form inside the egg; there are also a few salamander species that give birth to live young, so there's no one specific path these animals take to reproduce!

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