Introduction
The classification of tiger salamanders seems to be an ongoing process, as species have been re-classed numerous times. In the past, the California tiger salamander (Ambystoma californiense), and the Mexican tiger salamander (Ambystoma velasci) were considered subspecies or members of the taxon Ambystoma tigrinum, the Easter tiger salamander, but are now both considered separate species. Recently, the barred subspecies of A. tigrinum, A. t. mavortium, was also elevated to species level, and all remaining subspecies of A. tigrinum placed within this new taxon, retaining their subspecies names. For the remainder of this text, A. mavortium and A. tigrinum will simply be referred to as tiger salamanders.

Larval tiger salamanders are often confused with Ambystoma mexicanum (the axolotl) due to their similar appearance. There are some major differences between the two species, however, the most prominent being that axolotl's do not spontaneously metamorphose in captivity, whereas tiger salamanders do. So, you can probably imagine the problems incurred when someone purchases what they thought was a fully aquatic axolotl and discovers that it transforms into a large terrestrial salamander. The trained eye can easily distinguish the two species based on minor physical differences, including size, color, and toe and snout shape. Axolot's will attain much larger lengths than tiger salamander larvae, and so anything over 4-5 inches is likely an axolotl. Axolotl's also possess longer toes, and less-blunt snouts. Color is also an indicator, as axolotl's are often found in rarer color morphs, such as albino, leucistic, axanthic, and melanoid. The wild type axolotl is perhaps the most similar in appearance to the larval tiger salamander, with an olive green to grayish dorsal coloration, mottled with black or brown. In addition to the previously described physical differences, the wild type axolotl can be distinguished from the larval tiger salamanders by the presence of higher levels of dark mottling about the body (in most cases).

Further misrepresentation occurs from the use of incorrect vernacular names (common names). Larval tiger salamanders and axolotl's are often lumped into the same species, and then mislabeled "waterdogs". There's two mistakes here; first, these two are not the same species, and second, neither of them are waterdogs. The name waterdog, and mudpuppy for that matter, are reserved for the genus Necturus, in the family Proteidae. Waterdogs and mudpuppies are large, paedomorphic caudates that superficially resemble axolotl's and waterdogs, but are more obviously distinguishable. Waterdogs possess a more variable color patterns, lower tail fins, notably thick skulls, and often remarkably bright red, fluffy gills. Waterdogs and mudpuppies are also much larger, and can be definitively distinguished by the presence of four toes and four fingers, whereas axolotls and larval tiger salamanders possess five toes and four fingers.

So, when presented with a "waterdog" in the pet store or elsewhere, be aware that it may not be a true "waterdog", and could possibly be an axolotl or larval tiger salamander. Also be aware that only axolotl's are fully aquatic, and larval tiger salamanders will transform into a large, terrestrial salamander.

For clarity, the photos below show the physical differences between tiger salamander larva, axolotl's, and waterdogs. 

Larval tiger salamander (A. m. mavortium); Note the shorter, blunter toes, and olive greenish color with minimal spotting. Photo © Suzanne L. Collins, cnah.org	Wild type axolotl (A. mexicanum); Axolotl with similar coloration to a larval tiger salamander.	Waterdogs (Necturus alabamensis, and Necturus lewisi); Photos © Suzanne L. Collins, cnah.org
Albino axolotl (A. mexicanum); Albinism is less common in larval tiger salamanders. Photo © Jessica Miller	Leucistic axolotl (A. mexicanum); Photo © Jessica Miller	Melanoid axolotl (A. mexicanum);  Photo © Jessica Miller

A. m. mavortium. Photo © Suzanne L. Collins, Center for North American Herpetology

Ambystoma mavortium melanostictum (Blotched Tiger Salamander):
The dorsum is dark and mostly covered yellow to olive or gray blotches. A. m. melanostictum is found in south British Columbia, east Washington and Alberta to south Wyoming and northeast Nebraska.

A. m. melanostictum. Photo © Suzanne L. Collins, Center for North American Herpetology

Ambystoma mavortium nebulosum (Arizona Tiger Salamander):
The dorsum is black or dark gray with small, light-yellow blotches or bars that cover the body from head to tip of tail, except for the ventral area. Some specimens may have their color pattern reversed, making them appear very similar to A. m. diaboli.

A. m. nebulosum. Photo © Suzanne L. Collins, Center for North American Herpetology

Ambystoma mavortium stebbinsi (Sonora Tiger Salamander, Huachuca Tiger Salamander):
The dorsum is black or dark gray with smaller, rounded, yellowish spots that also cover the tail. The ventral area is typically light to medium brown, and the head is typically black. This subspecies has been federally listed as endangered throughout its entire range (Huachuca and Patagonia Mountains in Arizona).

Ambystoma tigrinum  (Eastern Tiger Salamander):
The dorsum is dark with olive to brownish spots that expand at the tip of tail.

A. tigrinum. Photo © R.D. Bartlett

Tiger Salamanders in Captivity

For Larval Tiger Salamanders:
A semi-aquatic vivarium (land/water) setup is ideal for housing larval tiger salamanders. Although larvae are aquatic, they will need a land area to emerge onto when they metamorphose. Upon metamorphosis, they can be relocated to a more suitable terrestrial setup if the existing tank is not adequate. For larval tiger salamanders, the tank should be mostly water, with an adequately-sized, easily-accessible land area for new morphs to emerge onto. The land area can consist of mossy rocks, large driftwood pieces, or elaborate earthen shores.  It is important to provide both terrestrial and aquatic environments during the entire metamorphosis and usually for a period after, as new morphs often traverse between land and water until they are completely comfortable in their new terrestrial home. See article 0006 - Water Quality and Amphibians and article 0009 - Introduction to the Nitrogen Cycle for more information on water quality and the nitrogen cycle. 

The water level can be 10-30 inches deep, or even deeper if possible, and can support a filter with a carbon and sponge insert, or a canister type biological filter for larger tanks. The filter should not create a strong current or disturbance, as strong filters can overload the water with dissolved gas content, which can cause health problems for the inhabitants. Strong filtration may also stress the larvae if they must fight the current to reach the surface or move about the tank. Most filters can be positioned so that the output is facing the side of the tank, or rocks or thick vegetation can block and slow the output if it cannot be re-positioned. Internal filters  with adjustable flow rates are ideal for small to medium sized larvae tanks. When adjusted properly these types of filters provide just enough filtration and aeration. If a filter is not included, a partial water change (10%-20%) should be done weekly or biweekly. Tiger salamanders are sensitive to water chemistry, so it is recommended to keep a freshwater test kit on hand and regularly check the pH, ammonia, nitrite, and nitrate levels. Gravel is the standard form of submersed substrate, but keep in mind that the larvae are capable of ingesting bite-sized gravel. Larger rocks that won't be eaten, or sand can also be used. Bare bottom tanks have also been used, but can inhibit locomotion, especially glass tanks, and so are not recommended. Live aquatic plants should be included in the water area to aid in chemical regulation and to serve as hiding places. Guppies can be added to the water when the larvae are larger than 3-3.5 inches, but may be eaten. Also, guppies reproduce rapidly and will thrive in a temperate tank. If guppy populations grow too numerous, they can overwhelm the inhabitants, and drive them away from food sources. See article 0020 - Captive Habitats: Ideas, Instructions, and Examples and the Captive & Wild Habitats section of the Photo Gallery.

As with all amphibians, tap water should be treated with a water conditioner or primer prior to the introduction of inhabitants. Never used plain tap water, de-ionized, distilled, or reverse osmosis water alone with amphibians. Also, the tank should be properly cycled (nitrogen cycle) prior to the introduction of amphibians. See article 0006 - Water Quality and Amphibians and article 0009 - Introduction to the Nitrogen Cycle for more information about water quality and the importance of the nitrogen cycle.

For Terrestrial Adults:
Transformed tiger salamanders are fossorial, meaning they burrow into the substrate. In the wild, they may dig their own burrows in soft, moist soil, or inhabit abandoned burrows made by other animals. In captivity, their terrarium should consist of moist, lightly-packed soil. A few inches of soil should suffice, but more will be needed if live plants are included. The top few inches of soil should be slightly loose to allow for easy burrowing. Soil should be biologically active, supporting a wealth of beneficial microbes. Biologically active soil can be collected from pollutant-free outdoor sources, or created by mixing several sterile substrates with a starter culture of natural leaf litter from the wild (see article 0021 - Substrate Mixtures for the Vivarium for more information). It is a good idea to provide small caves and shelters made of rock, wood, terra cotta, or other non-toxic materials, as well. The soil must always be kept adequately, but not soaking wet or muddy. Although breeding is seldom in captivity, tiger salamanders require a large, rather shallow water area of about 5-12 inches deep. Such a water area should be at least a few gallons in volume, and well cycled. Large tanks can be sectioned off for a water area on one side and a land area on the other. Bog type environments that gradually ascend into moist and drier areas are also acceptable (see article 0021 - Substrate Mixtures for the Vivarium for more information about bogs). Water bowls will not suffice for breeding, and should be excluded from the enclosure for sanitation reasons. See article 0020 - Captive Habitats: Ideas, Instructions, and Examples and the Captive & Wild Habitats section of the Photo Gallery.

Breeding

Feeding 

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