Mole salamanders facts for kids

Quick facts for kids Mole salamanders
Spotted salamander (Ambystoma maculatum)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Amphibia
Order:	Urodela
Family:	Ambystomatidae
Genus:	Ambystoma Tschudi, 1838

Mole salamanders are a group of advanced salamanders found only in North America. They are famous for a few reasons. One is the axolotl (A. mexicanum), which is often used in science research because it stays in its baby form even as an adult. Another is the tiger salamander (A. tigrinum, A. mavortium), which is the official amphibian of many US states and is sometimes kept as a pet.

What Do Mole Salamanders Look Like?

An Ambystoma kansensis fossil (an ancient mole salamander)

Most adult mole salamanders live on land. They have wide, bulging eyes and thick arms. You can also see special grooves on their sides called costal grooves. Many species have bright patterns, like blue spots or yellow stripes, on a dark background.

These salamanders spend most of their lives underground in burrows. They might dig their own burrows or use ones left by other animals. In colder areas, some northern species will hibernate in these burrows during winter. They usually live alone and eat any small invertebrates they can find. Adults only go back to water, usually the ponds where they were born, when it's time to breed.

Life Cycle and Reproduction

All mole salamanders lay many eggs in clumps in the water. When the eggs hatch, the babies are called larvae. These larvae live completely in water. They have three pairs of feathery external gills behind their heads, which they use to breathe underwater. They also have large fins that run from their heads all the way to their tails.

Soon after hatching, larvae grow limbs. They have four toes on their front legs and five toes on their back legs. Their eyes are set wide apart and don't have eyelids yet.

Some larvae, especially in the southern parts of their range and tiger salamander larvae, can grow to adult size before they change into their adult form. This change is called metamorphosis. During metamorphosis, the larvae lose their gills and fins. Their tails, skin, and limbs become thicker, and their eyes develop eyelids. Their lungs also fully develop, allowing them to live on land.

Neoteny: Staying Young Forever

Some mole salamander species, and even some groups of species that normally live on land, are neotenic. This means they keep their larval (baby) form even when they become adults. The most famous example of this is the axolotl. Neotenic salamanders can't produce a special hormone called thyroxine that helps them change. If they are given this hormone from outside, they can sometimes change into a land-dwelling form, but this usually makes them live shorter lives.

Tiger Salamander Family

A Tiger salamander (Ambystoma tigrinum)

It used to be hard to tell different mole salamander species apart, especially within the "tiger salamander complex." This is because some populations stay in their larval form, and many tiger salamanders look very similar. They all have big heads, small eyes, and thick bodies. This might be because they have the original body shape of mole salamanders. They are also the largest mole salamanders and have very big larvae.

Even though they look similar and have similar lives, scientists found that tiger salamanders from far apart places are actually different species. Their living areas can overlap, and they sometimes breed with each other, which makes it even harder to tell them apart.

Over time, scientists have used new methods, like studying their genes, to identify different species. For example, the barred tiger salamander (A. mavortium) is now considered its own species. The California tiger salamander (A. californiense) was also found to be very different from other mole salamanders. The Plateau tiger salamander (A. velasci) was identified as a separate species in 1997. Scientists now believe that the axolotl (A. mexicanum) is not closely related to the tiger salamander (A. tigrinum) as once thought. Instead, the axolotl is likely closely related to the Plateau tiger salamander, as they live in the same area.

All-Female Salamander Groups

There are also special populations of mole salamanders that are all female. These groups are found in the Great Lakes region and northeastern North America.

Amazing Limb Regeneration

The axolotl (Ambystoma mexicanum) is a neotenic salamander famous for its amazing ability to regrow lost limbs. This makes it a very important animal for scientists who study how bodies can repair themselves.

When an axolotl regrows a limb, a special group of cells forms called a blastema. These cells can multiply quickly and turn into different parts of the new limb. During this process, the cells can get tiny breaks in their DNA. But the axolotl's cells are very good at fixing this DNA damage using a process called homologous recombination, which helps them rebuild the limb perfectly.

Naming and Classification

A family tree showing how different Ambystoma species are related. For example, the Ambystoma macrodactylum and Ambystoma laterale are very close relatives.

A group of salamanders called Rhyacosiredon used to be thought of as a separate type of salamander. But after studying them more closely, scientists realized that these salamanders are actually more closely related to some Ambystoma species than those Ambystoma species are to each other. This means Rhyacosiredon should be part of the Ambystoma group. Their unique body shape, which helps them live in streams, might have made scientists think they were a different group at first.

The name Ambystoma was given by Johann Jakob von Tschudi in 1839. It's usually thought to mean "cup-mouth." Tschudi didn't explain why he chose the name, so some people thought he meant to write Amblystoma, which means "blunt-mouth." You might even see old records using the name Amblystoma. However, since there's no clear proof that Tschudi made a mistake, the name Ambystoma is still used today.

Species of Mole Salamanders

There are 32 known species in the Ambystoma group. The newest one discovered is A. bishopi. Some of these species live on land, some stay in their larval (neotenic) form their whole lives, and some species have populations that do both!

Image	Species and author	Common name	Distribution	Lifestyle	IUCN status
	A. altamirani Dugès, 1895	Mountain stream salamander, Achoque	Central Mexico, west and south of the Valley of Mexico	Terrestrial and neotenic
	A. amblycephalum Taylor, 1940	Blunt-headed salamander	West-central Mexico (Michoacán state), near Morelia	Terrestrial and neotenic
	A. andersoni (Brandon and Krebs, 1984)	Anderson's salamander	West-central Mexico (Michoacán state), Laguna de Zacapu	Neotenic
	A. annulatum Cope, 1886	Ringed salamander	South-central United States (Arkansas, Illinois, Missouri, Oklahoma), Ozark Plateau and Ouachita Mountains	Terrestrial
	A. barbouri Kraus & Petranka, 1989	Streamside salamander	South-midwest United States (Indiana, Kentucky, Ohio, Tennessee, West Virginia)	Terrestrial
	A. bishopi Pauly, Piskurek & Shaffer, 2007	Reticulated flatwoods salamander	Southeast United States (Florida Panhandle and southernmost Georgia), west of the Apalachicola-Flint River	Terrestrial
	A. bombypellum (Taylor, 1940)	Delicate-skinned salamander	Central Mexico (State of Mexico) near Jilotepec	Terrestrial
	A. californiense Gray, 1853	California tiger salamander	Central Valley of California	Terrestrial
	A. cingulatum Cope, 1868	Frosted flatwoods salamander	Southeast United States (southern South Carolina and Georgia south to northern Florida)	Terrestrial
	A. dumerilii (Dugès, 1870)	Lake Pátzcuaro salamander, Achoque	West-central Mexico (Michoacán state), Lake Pátzcuaro	Neotenic
	A. flavipiperatum Dixon, 1963	Yellow-peppered salamander, Ajolote de Chapala	West-central Mexico (Jalisco)	Terrestrial
	A. gracile (Baird, 1859)	Northwestern salamander	Northwest North America (southernmost Alaska to northern California)	Terrestrial
	A. granulosum Taylor, 1944	Granular salamander, Ajolote	Central Mexico (State of Mexico) near Toluca	Terrestrial
	A. jeffersonianum (Green, 1827)	Jefferson salamander	Northeastern North America (Ontario south to Virginia and west to Illinois)	Terrestrial
	A. laterale Hallowell, 1856	Blue-spotted salamander	Northeastern North America (Nova Scotia west to Manitoba and Minnesota and south to Indiana and New Jersey)	Terrestrial
	A. leorae Taylor, 1943	Leora's stream salamander, Ajolote	Central Mexico (Mexico state - Puebla border), Mount Tlaloc	Terrestrial
	A. lermaense (Taylor, 1940)	Lake Lerma salamander	Central Mexico (State of Mexico), Lake Lerma near Toluca	Terrestrial and neotenic
	A. mabeei Bishop, 1928	Mabee's salamander	Coastal southeast United States (southeast Virginia to South Carolina)	Terrestrial
	A. macrodactylum Baird, 1950	Long-toed salamander	Northwest North America (Alaska south to northern California and east to Alberta and Montana)	Terrestrial
	A. maculatum (Shaw, 1802)	Spotted salamander	Eastern North America (Nova Scotia west to Wisconsin and south to eastern Texas and Georgia)	Terrestrial
	A. mavortium Baird, 1850	Barred tiger salamander	Western North America (Manitoba south to Texas and west to Washington and California)	Terrestrial and neotenic
	A. mexicanum (Shaw and Nodder, 1798)	Axolotl	Central Mexico (State of Mexico), Lake Xochimilco	Neotenic
	A. opacum (Gravenhorst, 1807)	Marbled salamander	Eastern United States (New Hampshire south to northern Florida and east to Missouri and Texas)	Terrestrial
	A. ordinarium Taylor, 1940	Puerto Hondo stream salamander	West-central Mexico (Michoacán state), Puerto Hondo stream	Terrestrial and neotenic
	A. rivulare Taylor, 1940	Michoacan stream salamander	Central Mexico (western State of Mexico)	Terrestrial and neotenic
	A. rosaceum Taylor, 1941	Tarahumara salamander	Northwest Mexico, Sierra Madre Occidental	Terrestrial and neotenic
	A. silvense Webb, 2004	Durango salamander	Northwest Mexico (Durango and Chihuahua), Sierra Madre Occidental	Terrestrial and neotenic
	A. talpoideum Holbrook, 1838	Mole salamander	Southeast United States (Virginia west to Oklahoma and south to northern Florida)	Terrestrial and neotenic
	A. taylori Brandon, Maruska, and Rumph, 1982	Taylor's salamander	Southeast Mexico (Puebla), Laguna Alchichica	Neotenic
	A. texanum Matthes, 1855	Small-mouth salamander	South-central United States (Ohio west to Nebraska and south to Texas and Alabama)	Terrestrial
	A. tigrinum (Green, 1825)	Eastern tiger salamander	Eastern North America (New York northwest to Manitoba and south to Texas and northern Florida)	Terrestrial and neotenic
	A. velasci (Dugès, 1888)	Plateau tiger salamander	Mexican Plateau	Terrestrial and neotenic

Sometimes, two groups of all-female hybrid populations are also given their own species names:

• Silvery salamander (A. platineum)
• Tremblay's salamander (A. tremblayi)

See also

In Spanish: Ambystoma para niños

• Oophila amblystomatis