Mole salamander

Mole salamanders are a special group of animals called Ambystoma. They live only in North America and are part of the advanced salamanders family.

One famous mole salamander is the axolotl. Scientists study axolotls to learn how some animals can keep their baby features forever.

Another well-known mole salamander is the tiger salamander. Many people keep tiger salamanders as pets. It is also the official amphibian in four US states.

These amazing creatures help us learn more about nature and animal life.

General description

Mole salamanders have big eyes, lines along their sides, and strong arms. They often have bright blue spots or yellow bars on their dark skin. These salamanders live mostly underground in burrows. Sometimes they dig their own burrows, and sometimes they use burrows made by other animals. Some northern types may stay underground all winter. They live alone and eat insects and other small creatures. Adults usually only come out of the water to return to their birth ponds to lay eggs.

All mole salamanders lay large eggs in water. Their babies, called larvae, live in water and have gills to breathe. These larvae have long fins and grow limbs with four toes on their front legs and five toes on their back legs. Their eyes are wide apart and don’t have eyelids. Some larvae can grow as big as adults before they change into their adult form, a process called metamorphosis. During this change, they lose their gills and fins, grow thicker skin and limbs, develop eyelids, and get lungs to live on land. One famous type of mole salamander is the axolotl, which keeps its larval features into adulthood because it cannot make a certain substance needed to change fully into an adult.

Tiger salamander complex

Tiger salamanders (Ambystoma tigrinum complex) have big heads, small eyes, and thick bodies. They are some of the largest mole salamanders and have relatively big larvae.

These salamanders live in many different places across North America. Because of this wide range, different groups of tiger salamanders look and act in various ways. Scientists are still studying whether these groups are separate species or subspecies and what causes them to change over time. Some groups that used to be considered part of Ambystoma tigrinum are now recognized as their own species. For example:

1. Ambystoma mavortium (barred tiger salamander) includes former subspecies like A. t. diaboli, A. t. mavortium, A. t. melanostictum, A. t. nebulosum, and A. t. stebbinsi.
2. Ambystoma californiense (California tiger salamander)
3. Ambystoma velasci (Plateau tiger salamander), which lives in the same areas as the axolotl (A. mexicanum)

Hybrid all-female populations

Some mole salamanders are special because they are all-female groups found in the Great Lakes region and northeastern North America. These females need sperm from related species to help their eggs start growing, but the eggs usually grow without using the sperm’s genes. Sometimes, they add the sperm’s genes to their own babies.

These all-female salamanders can have genes from up to five different species, such as the blue-spotted salamander, Jefferson salamander, small-mouthed salamander, streamside salamander, and tiger salamander. This mixing creates many different types of these salamanders. Even though their bodies look similar to other salamanders, their genetic makeup is very unique. Scientists believe these all-female salamanders are one of the oldest known groups of animals that only have females.

Limb regeneration

The Ambystoma mexicanum, a type of salamander, keeps its baby-like looks. It is very good at growing back lost body parts. Scientists study these salamanders to learn more about how limbs can grow again. When a limb is lost, special cells called blastema form and help make a new limb. These cells need to fix their DNA to work right. This is an important part of how regeneration happens.

Taxonomy

Mole salamanders are part of a family called Ambystomatidae. Scientists used to think one group of these salamanders, called Rhyacosiredon, was its own special family. But later studies showed that Rhyacosiredon is very close to some Ambystoma species. This means Ambystoma includes animals that are not all directly related.

The name Ambystoma was created in 1839 by a scientist named Johann Jakob von Tschudi. Some people think he may have meant to write Amblystoma, which means "blunt-mouth." But because we do not know for sure, the name Ambystoma is the one we use today.

Species

The genus Ambystoma has 32 different types of salamanders, including A. bishopi. Some of these salamanders live mostly on land, while others keep their gills and stay in water their whole lives. There are even some groups that have both kinds living together.

There are also two special groups of salamanders that can only have babies with others of the same group. These are called the Silvery salamander (A. platineum) and Tremblay's salamander (A. tremblayi).