Tiger snakes are a highly venomous snake species found in southern regions of Australia, including Tasmania. They belong to the genus Notechis and family Elapidae. Tiger snakes are relatively large, growing up to 2 meters (6.6 feet) in length, and are notable for their extremely potent venom. Their diet consists primarily of small animals that can be consumed whole, including frogs, lizards, small mammals, and even other snakes.
Frogs
Frogs make up a substantial part of the diet of tiger snakes. As frogs are abundant across the wetland habitats preferred by tiger snakes, they provide a readily available food source. Tiger snakes have been observed to actively hunt for frogs during their nocturnal activity periods. Their venom allows them to rapidly subdue and kill frogs before consumption. Some key frog species eaten by tiger snakes include:
– Common eastern froglet
– Spotted grass frog
– Striped marsh frog
– Peron’s tree frog
– Green and golden bell frog
Tiger snakes are able to swallow adult frogs whole and digest their bodies rapidly. Their flexible jaws allow them to consume even some of the larger frog species. Frogs provide tiger snakes with hydration as well as key nutrients like proteins, vitamins, and minerals.
Lizards
Lizards are another major component of the diet of tiger snakes. Slow-moving species which inhabit the ground and low vegetation are especially vulnerable to predation by tiger snakes. Smaller lizard species can be swallowed whole, while larger lizards are subdued with venom before being consumed. Lizards offer nutrients including proteins, fats, calcium, and vitamin D. Some lizards frequently eaten by tiger snakes include:
| Common Name | Scientific Name |
|---|---|
| Eastern water skink | Eulamprus quoyii |
| Grass skink | Lampropholis delicata |
| Garden skink | Lampropholis guichenoti |
| Southern grass skink | Pseudemoia entrecasteauxii |
The tiger snake’s heat-sensitive pits allow them to precisely strike at lizards during the day or night. Their speed and highly toxic venom make lizards easy prey. The bones and scales of lizards are digested along with the flesh.
Small Mammals
Although not as frequently eaten as frogs and lizards, small mammals are also a food source for tiger snakes. Mammals offer nutrient-dense sources of protein and fat for sustaining tiger snakes. Some mammals found within the tiger snake’s habitat that may be vulnerable to predation include:
| Common Name | Scientific Name |
|---|---|
| House mouse | Mus musculus |
| Swamp rat | Rattus lutreolus |
| Bush rat | Rattus fuscipes |
| Common wombat | Vombatus ursinus |
The availability of mammals is often dependent on habitat. In wetlands, swamp rats may be frequently consumed, while bush rats and introduced mice are likely prey in forested areas. Baby wombats may also occasionally fall victim to predation by tiger snakes.
Other Snakes
Though not a primary food source, tiger snakes have been documented consuming smaller snakes on occasion. Cannibalism of juvenile tiger snakes by adults has been observed when hunger drives them to eat any prey they can overpower. Other snake species small enough to be swallowed whole, like blind snakes and small elapids, may also contribute minor supplemental nutrition to the tiger snake’s diet on rare occasions.
Hunting Strategy and Prey Subjugation
Tiger snakes employ a mix of active hunting and ambush strategy to secure prey. They often utilize cover around wetlands, keeping their bodies hidden while positioning their heads to watch for passing prey movement. When prey is spotted within striking distance, the tiger snake quickly attacks. They also actively traverse their home ranges, poking their heads into cavities and thoroughly exploring for any hidden prey.
The extremely potent neurotoxic and coagulotoxic properties of tiger snake venom enable them to rapidly immobilize and kill prey after striking. Even relatively large prey like adult lizards or rats will quickly succumb to the toxic effects of the venom. Prey is then consumed head first to minimize the chances of retaliation by any prey not fully deceased.
Digestion
A tiger snake’s flexible jaws allow it to ingest prey items that are significantly larger than the diameter of its own head. The snake’s stomach also has the capacity to distend significantly in order to accommodate large meals. Powerful acids and enzymes within the stomach quickly break down flesh, scales, bones, and other body structures of consumed prey. Digestion is very rapid, enabling tiger snakes to profit from and reuse the energy in their prey.
Waste products are consolidated within the colon and cloaca before being passed out through the vent as a pellet of uric acid and other compounds. By digesting and concentrating waste for elimination in this manner, tiger snakes can minimize the amount of energy and hydration lost during digestion.
Energy Requirements and Frequency of Feeding
The energy requirements of tiger snakes depend on factors like body size, age, growth rates, and availability of prey within their habitat domains. When prey is plentiful, tiger snakes may eat frequently, consuming prey whenever the opportunity arises day or night. When prey is harder to find, tiger snakes can survive on less frequent but larger meals. Juveniles need to eat more frequently than adults to support higher growth rates.
On average, the typical tiger snake consumes the equivalent of about 10-20% of its own body mass per week. A 1.5 meter adult tiger snake weighing 500g, for example, would need to eat around 50-100g of prey weekly. This equates to ingesting a couple of decent sized frogs, lizards, or small mammals on a regular basis.
Risks to Tiger Snakes
While tiger snakes are formidable predators, they do face a range of risks from other predators:
| Predator | Risks Posed |
|---|---|
| Larger snakes | Larger snake species may prey on juvenile tiger snakes |
| Birds of prey | Birds like hawks and owls prey on small snakes |
| Wild canids | Foxes, wild dogs, dingoes may kill and eat even adult tiger snakes |
| Domestic cats/dogs | Pet cats and dogs also pose risks of predation to tiger snakes of all sizes |
Vehicles and habitat clearing by human activities also poses substantial risks to tiger snake populations in many areas. Tiger snakes help control populations of rodents, frogs, and other prey species, and are an iconic component of the Australian wildlife heritage. Preserving their habitat is key to the continued success of this unique apex predator.
Key Facts About the Tiger Snake’s Diet
Preferred Prey
– Frogs and lizards are staples of the tiger snake diet
– Small mammals supplement their nutrition
– Juvenile snakes may also be eaten
Hunting and Predation
– Actively hunts prey as well as utilizes ambush strategy
– Incredibly potent venom enables swift immobilization of prey
– Heat-sensitive pits aid detection of warm-blooded prey
Digestion and Energy
– Very flexible jaws allow ingestion of large prey
– Powerful stomach acids rapidly digest prey items
– Adult snakes consume ~10-20% of body mass weekly
Conclusion
The diet of the tiger snake allows it to thrive across a range of habitats in southern Australia and Tasmania. A generalist predator, it consumes a variety of prey including frogs, lizards, and small mammals. Its highly specialized hunting adaptations, toxic venom, and flexible digestive system enable the tiger snake to secure and process this diverse diet. Preserving the wetlands and forests this iconic snake inhabits will be crucial to protecting its future.
