Unveiling the Tiger Salamander's Diet: What Fuels This Mysterious Predator?

Tiger salamanders ( Ambystoma tigrinum ) are among the most widespread salamanders in North America. They are popular among amphibian enthusiasts due to their hardy nature and relatively simple care requirements. This article delves into the intricate details of the tiger salamander's diet, covering everything from their natural prey in the wild to optimal feeding practices in captivity.

Morphology and Habitat

Tiger salamanders exhibit a fascinating life cycle, starting as aquatic larvae with tail fins and gills. These larvae are characterized by alternating dark and light blotches down their backs and pale stripes along their sides. Adult tiger salamanders, in contrast, possess broad heads, thick bodies and tails, blunt noses, and small eyes. While both sexes appear similar, females typically have slightly shorter tails than males. These salamanders have four toes on their front feet and five on their back feet.

Notably, tiger salamanders have two distinct feeding morphologies: typical and cannibalistic. The cannibalistic morph is distinguished by slimmer bodies, wider heads, and larger teeth compared to the typical morph.

The western tiger salamander (Ambystoma mavoritum) can be found from Texas to Canada and from the Dakotas to Oklahoma. The barred tiger salamander (Ambystoma mavoritum mavortium) is one of five subspecies and is found from central New Mexico eastward through Texas.

Tiger salamanders inhabit diverse environments, including grasslands, semi-deserts, deciduous and coniferous forests, and woodlands near water. The cannibalistic morph is more prevalent in drier areas and shallow waters where competition is intense.

Read also: Tiger River Spa Maintenance Tips

Natural Diet in the Wild

Both larval and adult tiger salamanders consume a variety of small invertebrates. Adult tiger salamanders commonly feed on beetles, earthworms, and crickets. They also consume vertebrates, such as tadpoles, lizards, small snakes, and even baby mice. While the larval stage is entirely aquatic, adult tiger salamanders are primarily terrestrial and nocturnal. They spend much of their time underground in burrows, which helps them avoid high temperatures and predators.

Dietary Needs in Captivity

In captivity, tiger salamanders should be fed a varied diet consisting primarily of gut-loaded insects and worms. They are carnivores and will eat almost any prey they can fit in their mouths, being attracted to the movement of the prey. They generally ignore dead prey and food pellets.

Recommended Food Items

Earthworms and Night Crawlers: These are excellent food sources due to their nutritional content and optimal calcium-to-phosphorus ratio. Night crawlers may need to be cut into pieces for smaller tiger salamanders. Watching a tiger salamander eat a worm is often described as watching someone 'slurp' a piece of spaghetti.
Red Wiggler Worms: These smaller earthworms, growing to about 2 inches (5 cm), are also nutritious. However, they may be unpalatable due to a foul-smelling yellow liquid they exude when chopped, making them best fed whole.
Crickets: While crickets are a readily available food source, they are a poor source of calcium and have a low calcium-to-phosphorus ratio. If crickets are the sole food source, this imbalance can lead to metabolic bone disease in the amphibian.
Roaches: Roaches are another suitable option for feeding tiger salamanders.
Beetles: Beetles can be part of a varied diet for tiger salamanders.
Superworms: Superworms can be offered as part of the diet.
Waxworms: These are high in fat and have a poor calcium-to-phosphorus ratio, so they should be fed rarely and only to fatten up a thin tiger salamander.
Silkworms: Silkworms are a nutritious option for tiger salamanders.
Hornworms: Hornworms can be included in the diet.
Phoenix Worms: Although high in fat content, phoenix worms have a good calcium-to-phosphorus ratio.
White Worms: White worms can be another addition to the diet.
Pinky Mice: Occasionally, pinky mice can be offered, but tiger salamanders can easily become obese, so pinkies should be fed rarely.

Gut-Loading and Dusting

Crickets and most other feeder insects are poor sources of calcium. To enhance the calcium content of crickets, two methods can be used: gut-loading and dusting.

Gut-loading: This involves feeding crickets a diet enriched with vitamins and high in calcium. Commercial and homemade formulations can be used. The gut-loading process should start 48 hours or more before feeding the salamander. Crickets begin to lose calcium in their feces quickly and should be consumed within a few hours of being offered to the salamander.
Dusting: This involves dusting crickets with a good quality vitamin/mineral product in addition to a calcium preparation, such as Herptivite multivitamins plus Rep Cal's Calcium with Vitamin D3 or other preparations with similar vitamin/mineral content. These supplements should be stored in a cool, dry area and replaced every six months once opened due to vitamin degradation. Crickets should be dusted directly before feeding the salamander, as the dust will be lost through movement and when crickets groom themselves. A simple way to dust crickets is to place them in a small plastic bag with the vitamin and calcium supplement, close the bag, and shake a few times. The crickets will be covered with a thin layer of powder. Dusting frequency is empirical, but keepers commonly feed dusted prey one to two times per week.

Feeding Frequency and Amount

When the vivarium is maintained around 72°F (22°C), tiger salamanders should be fed two to three times a week. The lower the temperature, the less often the salamander needs to be fed; if the enclosure is maintained at 60°F (16°C) or less, feeding once a week may suffice. In the winter months, tiger salamanders often have a decreased appetite, even when the enclosure is maintained at room temperature.

A general guideline is to offer the salamander as much as it will eat in several hours if using a food dish for worm pieces, phoenix worms, wax worms, etc., or if allowing prey such as crickets to roam free in the tiger's enclosure. It is especially important to remove all uneaten crickets, as they can bite and potentially harm the salamander if left in the vivarium too long. If hand-feeding, offer as much as the salamander will eat in about 10 minutes.

Read also: Learn About Marbled Salamanders

Feeding Methods

Food Dish: Worm pieces, phoenix worms, and wax worms can be placed in a food dish.
Free Roaming Prey: Crickets can be allowed to roam free in the tiger salamander's enclosure.
Hand Feeding: This allows precise knowledge of what the salamander has consumed. Long tongs or tweezers can be used to hand-feed, or the food item can be held and dangled from your fingers. For crickets and other large insects, holding the cricket by one back leg and placing it close to the salamander's head elicits a feeding lunge.

Important Considerations

Never move salamanders from their enclosure into another container to feed.
After eating, tiger salamanders may make facial gyrations, squeeze their eyes shut, or appear to yawn. This is normal and helps them move food down their digestive tract.

Enclosure and Environmental Factors

Enclosure Size and Ventilation

A single tiger salamander requires a minimum of a 15-gallon tank, while a 20-gallon tank or larger is recommended for housing multiple individuals to provide adequate space for exploration. The enclosure should be well-ventilated and secured with a screened lid to prevent escapes. If using an aquarium, a wire mesh top provides good ventilation. To provide adequate ventilation when using a plastic bin, multiple small holes should be drilled or melted with a hot glue gun into the container top and/or sides.

Temperature and Lighting

The optimal temperature range for the habitat is between 60°F and 75°F (15.5°C to 24°C). Direct sunlight should be avoided, as it can raise the temperature to harmful levels. A thermometer should be used to ensure that the temperature does not exceed 78°F (25.5°C), as overheating can cause stress and illness.

Data regarding the need for UV lighting are lacking. There is evidence to suggest that some forms of light, such as black lights, sun lamps, direct sunlight, and experimental exposure to UVB, may cause harm, including eye and skin damage in some amphibians. Tiger salamanders do well with a photoperiod provided by a regular fluorescent light. In the home environment, exposure to ambient light during the day with no lighting at night works well.

Humidity and Substrate

Humidity levels should be maintained at approximately 70%, which can be monitored using a hygrometer. To achieve and sustain proper humidity, the substrate should be misted daily with water. The substrate should be moist but not saturated. If it becomes overly wet, increased ventilation is recommended.

A substrate depth of at least 3-4 inches (7.6-10 cm) is recommended to accommodate the salamander's burrowing behavior. Ideally, half of the substrate should remain dry while the other half is slightly moist, allowing the salamander to choose its preferred environment. Suitable substrate materials include organic topsoil without vermiculite, chemicals, fertilizer, pesticides, manure, etc., or coco-fiber or a mix of the two. Coco-fiber is sold as compressed blocks which must be reconstituted to form a moist, fluffy substrate. Peat moss or soil mixes containing peat moss should be avoided, as peat moss is acidic and can cause skin irritation and electrolyte imbalance. Gravel should not be used, as tiger salamanders lunge at their prey and can ingest small gravel, leading to gut obstruction/impaction. Smooth rocks and stones can be used as decorations but should be larger than the size of the salamander's head to avoid accidental ingestion.

Read also: The Hoxsey Diet

The vivarium substrate should be able to break down organic matter such as feces, shed skin, and uneaten food. It must be able to maintain moisture without turning to mud, clumping, or drying out, and it should smell earthen and fresh. Substrates should not cause abrasion or irritation to the skin, which can potentially be a problem with jagged-edged wood chips or sharp bark slivers. Providing a moisture gradient will allow the salamander to self-regulate and seek out an appropriate micro-environment. This is best accomplished by allowing one end of the enclosure to be less moist than the other end.

Water

Untreated tap water should not be used in the care of caudates, as it may contain chlorine and/or chloramine, which are toxic to amphibians. Sterile water, distilled water, and de-ionized water also should not be used, as these are hypotonic and can lead to electrolyte disturbances in the salamander. Bottled spring water or municipal water that has been chemically treated to remove chlorine and chloramine is the preferred water for use with amphibians. Examples of products that may be used to remove chlorine and chloramine include Stress Coat+, AmQuel, and AquaSafe. Water used should have a pH between 6 and 8. Spring or treated tap water should optimally be used for all applications concerning the salamander: water for reconstituting coco-fiber bricks, water used when necessary to handle the salamander, water used for misting the enclosure, and water for the enclosure's water bowl, if using a water bowl.

In some municipalities, only chlorine is used to treat tap water. If only chlorine is in tap water, it may be removed by 'aging' the water in an open container to 'outgas' the chlorine; however, this process may take as long as a week and depends on several factors. Many municipalities now treat tap water with chloramine.

A shallow, heavy water dish can be provided but is not required. Some tiger salamanders appear to seek a water dish to take an occasional 'dip,' and a water bowl may provide a retreat for the salamander if the substrate becomes too dry or otherwise unsuitable. Fresh water should be placed in the dish every few days or when soiled by feces or substrate.

Hiding Places

Tiger salamanders are fossorial animals and are nocturnal. They require a moist but not wet substrate to allow for burrowing, and they need places to hide. These are not the most visible of salamanders, as they spend most of their time underground in their burrows or under hides. Pieces of driftwood, large flat stones, cork bark, and commercially available caves serve as excellent hides. Each adult animal should have at least one large hide. If a hole with an entrance is dug underneath a large flat hide or heavy water dish and the salamander is introduced to this 'cave', it will remain and/or return there, making locating the animal much easier. Fake silk or plastic plants can be added to make the vivarium more attractive. Live plants do not work well with tiger salamanders because these salamanders dig, and plants can be easily uprooted.

Maintenance

The vivarium should be spot-cleaned several times per week to remove uneaten food, shed skin, and feces. The substrate should be misted with water when it appears to be losing moisture. Misting frequency depends on several factors, such as the moisture retentiveness of the substrate, ambient temperature, and humidity. Misting once or more per day may be required in arid areas, whereas in humid climates, misting may only need to be done once weekly or less. Periodically, the substrate will need to be changed. How frequently this is done is often dependent on the type of setup being used and whether there is an active ecosystem established in the vivarium. A definite indicator for substrate change is a foul or sour odor. Another indicator of the substrate needing replacement is the emergence of fungus gnats. These small, grey/black flies look somewhat like tiny mosquitoes without the proboscis. Although these flies are not harmful to salamanders, they can be bothersome to humans, especially when they escape the enclosure and invade human living spaces.

When cleaning the enclosure prior to replacing the substrate, use very warm tap water and scrub the interior with a sponge, rinse with cold water, and then dry. Do not use soaps or detergents. If these products are used, the enclosure must be thoroughly rinsed and re-rinsed and dried before adding the substrate. Any equipment such as buckets and sponges used in caring for tiger salamanders should not be used for any other function. Generally, there is no need to disinfect an established vivarium; cleaning will suffice.

General Care Tips

Newly homed tiger salamanders may bury themselves in their substrate.
All habitats should be well-ventilated and secured with a screened lid to prevent the animal from escaping.
With proper care, salamanders reach their adult size within a year.
Always provide the largest habitat possible.
Salamanders must be monitored for aggressive behavior. If two animals fight, separate them.
Salamanders should get 10-12 hours of light exposure daily with the help of a low-watt incandescent bulb. This will imitate natural sunlight and help the animal establish a day/night cycle.
White lights should not be left on continuously, as they will disrupt the salamanders sleep cycle and negatively affect its overall health.
The bottom of a salamander’s tank should be lined with at least 3-4 inches of substrate to allow for burrowing.
Create a moisture gradient by keeping the substrate on one side of the enclosure moist while the substrate on the other side is drier. That way, the salamander can choose the side it prefers.
Salamanders like to burrow under driftwood, cork, or moss, and hide under plants or moss.
Using powder-free latex gloves moistened with dechlorinated water, move the amphibian to a secure habitat.
Scrub the empty tank and any furnishings with an amphibian-safe habitat cleaner or 3% bleach solution. The bleach solution should stay on the habitat for at least 10 minutes to ensure that the surfaces are properly disinfected.
Return the amphibian to the clean habitat.
Before feeding, dust their salamander’s insects with a powdered vitamin supplement.
To dust insects, place them in a bag or disposable plastic container along with a powdered supplement.
Gut-loaded diets are fortified with vitamins and minerals to help provide optimal nutrition to the amphibians that feed on them.
Pet parents should always use powder-free latex gloves moistened with dechlorinated water when handling an amphibian.
All amphibians have glands in their skin that can secrete toxins.
Healthy growing salamanders will shed their skin every few days or weeks.
Salamanders should be seen by a veterinarian once annually. They can be transported using an appropriately sized Tupperware container with airholes and a moistened surface such as wet papers towels on the bottom.

Handling

As with all amphibians, a tiger salamander's skin is semi-permeable and very sensitive to the environment. Because of this, the oils, salts, and other chemicals that may be on our hands can be harmful to the salamander. It is recommended to handle these animals as little as possible and to wash and thoroughly rinse hands before handling.

Health Considerations

Tiger salamanders, although immune themselves, can transmit the fungus Batrachochytrium dendrobatidis, which is a major worldwide threat to most frog species by causing the disease chytridiomycosis. They also carry ranaviruses, which infect reptiles, amphibians, and fish. Using tiger salamander larvae as fishing bait appears to be a major source of exposure and transport to wild populations. One of these ranaviruses is even named the Ambystoma tigrinum virus (ATV).

Conservation Status

In the southeastern United States, tiger salamander populations are experiencing declines, largely due to deforestation and the destruction of wetland environments. Research conducted by Harte and Hoffman in the Colorado Rockies suggests acid rain could be a contributing factor.

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