Newts & Salamanders By: DIANA LUONG

Newts

Newts are semi-aquatic amphibians that look a bit like a combination of a frog and a lizard. Like frogs, they have smooth, moist skin. As adults, they have long tails like lizards.

Sometimes people refer to newts as salamanders, and that's true. Newts are members of the scientific order Salamandridae. However, not all salamanders are newts. Newts are part of the subfamily known as Pleurodelinae.

Found throughout the waterways of North America, Europe, and Asia, newts develop in three distinct stages. They begin life as aquatic larvae. As they grow, they stay mainly on land and are called efts. When they reach adulthood, they have fully-developed lizard-like bodies.

Newts can boast some special features that make them unique creatures. For example, newts can regenerate missing body parts, including their arms and legs, eyes, intestines, jaws, heart, and spinal cord.

Salamanders

Salamanders are amphibians that look like a cross between a frog and a lizard. Their bodies are long and slender; their skin is moist and usually smooth; and they have long tails. Salamanders are very diverse; some have four legs; some have two. Also, some have lungs, some have gills, and some have neither — they breathe through their skin.

Salamanders belong to the order Caudata, one of three orders in the Amphibia class, along with Anura (frog and toads) and Gymnophiona (caecilians, which have no legs and resemble large worms). Within Caudata, there are nine families, 60 genera and about 600 species, according to the San Diego Zoo. Newts, mudpuppies, sirens and Congo eels (amphiumas) are all species of salamander.

History

Salamanders and newts all belong in the order Amphibia along with frogs and toads, ancestors of the first aquatic vertebrates to begin to colonize that other earthly environment - land. Comprising a mere 350 species out of the 4000 or so known species of amphibians, salamanders and newts are found only in the Americas and in the temperate zones of Northern Africa, Asia and Europe.

Grouping and characteristics

Many individuals wonder what the difference is between a newt and a salamander. Newts are actually a type of salamander. The true newts belong to the subfamily Pleurodelinae of the family Salamandridae. It should be noted that salamanders from other families may also be referred to as newts, i.e. the Primorye Newt (Salamandrella tridactyl) from the family Hynobiidae. Newts have three metamorphoses throughout their life, an aquatic larva, a terrestrial juvenile stage called an eft, and an adult stage. Although newts are associated with being more aquatic than other salamanders, this is not always the case. Adult newts can either be fully aquatic or semi-aquatic. Semi-aquatic forms live primarily terrestrial existences, but make annual returns to the water to breed.

Housing

Newts are well-adapted to life in the water, but do need a place to haul out and rest. The water in their aquarium can be deep, provided that egress is simple…cork bark, turtle platforms, and floating live or plastic plants all serve well as resting spots.

Newts are perfectly suited to aquariums stocked with live plants, and spectacular displays can be easily arranged (please see video below). Plants help maintain water quality, and the complex environments they create make life more interesting for both newt and newt-owner.

As newts readily climb glass, a secure screen cover is a must.

Feeding and Handling

Wild Salamanders

Salamanders that live in the water have gills like a fish and are quick, agile swimmers. A few of them have special bones that allow them to shoot out their tongues like cannons, but most aquatic species hunt by out-swimming their targets and catching them in their wide mouths. An aquatic salamander eats small fish, tadpoles, frogs, leeches, mosquito eggs and anything else that has the misfortune to fall into the water.

Baby Salamanders

Baby salamanders, or nymphs, go through a process of metamorphosis much like frogs. A freshly-hatched nymph is tiny and shaped like a tadpole. Even at a young age, the nymph has a row of sharp little teeth and is never a vegetarian. It eats its own eggshell and lives off of those nutrients for as much as a week while it grows and avoids predators. Once it is big enough to hunt on its own, the nymph begins to catch small aquatic animals like brine shrimp and plankton. As it grows, it moves on to bigger prey such as mosquito eggs, insect larvae and tadpoles. After about two months, the nymph is nearly full-grown and able to eat the same foods as an adult.

Pet Salamanders

It's all well and good to know the diet of wild salamanders, but what do salamanders eat in captivity? The good news is that salamanders are notoriously easy to feed. They are not very picky, and if an object is moving and small enough to fit into a salamander's mouth, it will be consumed with great relish in less than a second. You do, however, need to keep a salamander's nutritional needs in mind when feeding it. For land-dwelling salamanders, worms and other bugs available at most pet stores are the preferred diet. This includes crickets, earthworms, meal worms, maggots, buffalo worms and mosquito larvae. Aquatic salamanders require slightly different foods, with brine shrimp being the most common item on the menu. Other meals for these salamanders are worms such as earthworms or black worms; small fish like minnows; and larger shrimp such as ghost shrimp or crayfish.

Diseases

Chytridiomycosis

Chytridiomycosis is an often fatal infectious skin disease that seriously affects amphibians. The condition is caused by the chytrid fungus. Two types of this fungus has been responsible for huge die-offs in amphibian populations. Chytrid is one of the most devastating threats to amphibian populations.

Batrachochytrium salamandrivorans (Bs or Bsal)

The fungus Batrachochytrium salamandrivorans has been responsible for severe declines in salamander populations across Belgium and the Netherlands. The Fire Salamander (Salamandra salamandra), has been particularly impacted by Bsal. In some areas the population has declined so dramatically that it is now only 4 per cent of what it was in 2010. The mortality rate of Bsal is 96 percent. In fact Bsal has already extirpated fire salamander populations in northern Europe.

Batrachochytrium dendrobatidis (Bd)

The fungas Batrachochytrium dendrobatidis has been responsible for mass declines in amphibian populations. Devastatingly, Bd has been found on all of the continents where amphibians occur. It may be responsible for the greatest disease-caused loss of biodiversity in recorded history (Skerratt et al. 2007). Although, the fungus has impacted frogs more seriously, it does effect some salamander species. Furthermore, far less research has been conducted on salamanders, so Bd may affect them more then is currently thought. Bd has been implicated in the unexplained disappearances of Central American salamanders

Reproduction

Salamanders eggs are fertilized by the female picking up spermatophore from the ground or water where it was deposited by the male; the salamanders lay the fertilized eggs either in water or on land depending on the specific species and produce larvae that hatch with gills, a tail and weak legs. Salamanders evolve into adults that can breathe air, live on land and have strong legs.

During reproduction, a salamander can lay up to 450 eggs in the water. Salamander species that lay eggs on land rather than water lay significantly less eggs at one time, ranging from seven to 30. Aquatic larvae are easier to protect from predators and infection. The eggs have a toxic outer membrane that discourages predators from eating the rest of the nest.

The breeding season begins in late winter and lasts until early spring. Females are attracted by a male's spots, which he uses to lure a female towards him. He also makes fanning motions with his tail and emits a pheromone (sexual odor). When a female approaches, the male climbs onto her back and begins to rub his head on her snout. Males then deposit a sperm packet on the bottom of the pond and the female moves forward to pick it up. Males might compete with each other, but it is usually females who choose their mates.

It can take several weeks after breeding for females to lay their eggs. They lay a few eggs each day in different places. Females lay between 200 and 400 single, jelly-covered eggs on submerged plants each season. As soon as the process is finished, the female newt swims away leaving her eggs to survive on their own. Both males and females reach sexual maturity around the age of 3.

Credits:

Created with images by JessicaJohnson - "alpine newt amphibian newt" • mucorales - "fire salamander salamander animal" • lakewooducc - "newt eastern newt red eft" • Alois_Wonaschuetz - "fire salamander lizard nature" • elias_daniel - "Rough Skinned Newt" • Aah-Yeah - "Salamander" • jurvetson - "She turned me into a newt!"

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