Waterdogs are aquatic salamanders that transform themselves through metamorphosis – if conditions are right – into land-dwelling terrestrial tiger salamanders. They are relatively easy to care for and provide their owners with the experience of observing an animal evolve from living underwater to spending much of its life burrowed underground.
Waterdogs begin their lives looking something like small dachshunds with a tailfin and three pair of gills that stick out from behind their heads like feather plumes. Once begun, metamorphosis takes 12 to 18 months. Their gills shrink to nubbins and their lungs become fully functional, allowing them to come out of the water and to return to it only for breeding.
The term waterdog, as used in the pet industry, refers to the aquatic larval form of any one of the tiger salamanders, including the Arizona tiger salamander, Ambystoma tigrinum nebulosum. They are categorized in one of two ways. They may be merely young animals proceeding towards a normal metamorphosis and terrestrial adult life, or they may be neotenic (permanent larvae that attain sexual maturity but do not undergo metamorphosis).
The latter condition is usually the result of unsuitable water quality, probably due to a lack of iodine. Even then, though, if a waterdog is placed in an aquarium with good water, it is likely to transform into an adult in a matter of weeks or months.
These are voracious salamanders that consume all manner of smaller pond-dwelling creatures, and some populations are decidedly cannibalistic. Although they are usually 8 inches or less in length, some individuals may exceed 10 inches.
Waterdogs are entirely aquatic, but periodically rise to the water surface to gulp a breath of atmospheric air. Their water must be clean and chemical-free. All in the pet trade are wild-collected specimens.
Although waterdogs are readily available at many pet stores, they are more apt to be seen in the aquarium section than with other reptiles and amphibians. In some states these are prized as fish bait and the salamanders may be available at live-bait dealers.
Origin and Life Span
Collectively, tiger salamanders range over much of the central and eastern United States, as well as Canada and Mexico. Their metamorphosis from waterdogs to tiger salamanders can take a year to a year and a half and their full life span can range up to 25 years.
Waterdogs have three pair of bushy gills at the rear of their flattened head, rather long slender legs and a prominent tailfin that actually begins as a low ridge on the salamander's anterior trunk. Waterdogs lack eyelids. These salamanders are olive to olive-gray in coloration (there are no established aberrant colors), but may begin to develop darker or lighter colors as they near metamorphosis. Also at that point, the gills begin to reduce in size, eyelids develop and changes occur in the skin.
By the time they emerge from the water as gill-less, fully transformed adult tiger salamanders, the changes they have undergone are remarkable. At hatching the baby waterdog is about a half-an-inch long. At metamorphosis it may be up to 10 inches in overall length. The toes are flanged with translucent skin and the hind feet are weakly webbed.
Waterdogs are very tolerant to the cold and may remain active throughout the months of winter. Although having gills, waterdogs periodically surface to gulp a mouthful of fresh air. As they near metamorphosis, their air-gulping forays to the water's surface increase in frequency. Water that is too warm or otherwise unsuitable for long-term survival hastens gill-size reduction and ultimate transformation to the adult form.
They can be kept either in a planted or a non-planted aquarium. If in the former, you will need to provide suitable lighting to stimulate plant survival and growth. One or two can be kept in a 10-gallon tank, and three or four can live nicely in a 15- or 20-gallon tank.
Short of being very strongly acidic, pH of the water does not seem particularly important. We suggest that the water be well filtered but even with this the tank will require periodic changing. The more waterdogs you have and the larger they are, the more often the water will require changing.
The best water temperature for these waterdogs is between 60 and 75 degrees Fahrenheit. Pending metamorphosis will be indicated by decreasing gill size and an increase by the salamander in trips to the surface to breathe. At this time it is best to decrease water level, to only a couple of inches, and to provide a smooth haulout area (a piece of styrofoam or a floating plastic lily pad will do) that the salamander can access should it choose to do so. When metamorphosis is complete, the salamander will require a home in a woodland terrarium.
The diet of a wild waterdog will be heavy on aquatic insects, tadpoles, worms and other co-dwelling pond livers, occasionally including others of their own kind.
Captives eat earthworms, crickets, freshly killed minnows, tadpoles and glass (grass) shrimp. Reptomin®, pelleted trout chow, catfish chow and koi pellets are usually also eaten. Uneaten animal-protein based dietary items can quickly sour your water. Feed your waterdogs prudently.
They are voracious feeders that usually react in a frenzy when food is encountered. Food is found by sight, by scent and perhaps by touch.
Some waterdogs are actually cannibalistic and are capable of overpowering and eating remarkably large cagemates. They are better off in individual cages.
Handle your waterdog only with a soft, wet net. Scoop the waterdog up and cover the mouth of the net with your free hand to prevent the salamander from walking or flipping its way free. Get the waterdog back into the water as quickly as possible.
Waterdogs are hardy and largely trouble-free. If their water is too warm or water quality deteriorates, patches of fungus sometimes appear.
If waterdogs are kept communally, injuries can occur during feeding frenzies. Among the more typical injuries are injuries to or amputation of one salamander's gill stalk, leg, or piece of tailfin, by another. Serious though these injuries may look, larval ambystomatid salamanders are capable of regenerating the missing members.