Tasmania has three species of land snake:
Identifying a snake as it slides rapidly away can be difficult. Many people, quite sensibly, don't want to get too close. Even if you get close enough to see that it is a snake (it has no legs and has scales) there are still some difficulties. For example, tiger snakes, despite their name, do not necessarily have stripes and there is a lot of overlap in the body colouration of the three species of Tasmanian snakes. The most reliable distinguishing feature is the middle head scale; however, it is not recommended that you get so close as to be able to use this feature!
Pass the cursor over the species name to reveal the shape of the distinguishing middle head scale.
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Snakes move by throwing the body into a series of loops that move in waves from front to back, pushing the snake forward. This is why snakes are excellent swimmers and can actually move faster in water than on land. Many species of snake feed on eels, fish and frogs. Snakes can stay submerged for considerable periods. The fastest snakes are the most slender and have the smoothest skin. Snakes can also move in a caterpillar-like motion, by bunching up the front part of their body, pushing down and pulling the trailing part forward, then bunching up muscles in the back of the body, pressing down and pushing the front part forward. This method is used when moving slowly over smooth surfaces. There are rare reports of tiger snakes springing from a coiled position and jumping to escape. Although snakes can strike very quickly, they don't travel very fast at all. Their fastest pace on flat ground is about the same as a fast human walk.
Snakes depend on external sources of heat to raise their body temperature enough to become active, digest food and for the development of young within the body. Larger snakes take longer to warm and longer to cool. By taking advantage of radiant heat emitted from warmed objects and direct or reflected heat from the sun, snakes can raise their body temperature well above the air temperature. Snakes use posturing to warm up and maintain their body temperature, tending to stretch out as temperatures rise and to coil as temperatures drop. The dark colour of many Tasmanian snakes is an adaptation to a cold environment, enabling them to absorb heat more quickly than lighter coloured snakes. By doing this they can raise their body temperature quickly and become active, even in overcast conditions. Low environmental temperatures generally limit snakes activity to the warmer months between October and March. Over winter they become inactive and can go for many months without food. On very hot days snakes seek shade or water and will occasionally enter houses. If snakes get too hot they will die. Both tiger snakes and lowland copperheads can be active on warm nights, so be aware, and use a torch if walking about at night. On mainland Australia most snake species are at least partially nocturnal, and many are only active at night.
All Tasmanian snakes bear live young (viviparous). Larger snakes produce more young than smaller females of the same species. There is no maternal bonding between the young and adults. In fact, copperheads are well known to be cannibalistic, even eating their own babies.
All three Tasmanian species are capable of injecting venom, although the venom of the white-lipped snake has never been recorded as causing death to a human. Snakes have developed venom to subdue their prey as quickly as possible. Snakes are quite fragile creatures and having their vital survival equipment (eyes and tongues) in close proximity to their mouths means that attacking prey is a dangerous occupation. Highly toxic venom allows snakes to subdue potentially dangerous prey with minimum risk of injury to the snake. Venom is highly modified saliva and in some species of snakes is crucial to digestion. Venom is not designed specifically to kill people, although it can. Even dead snakes can be dangerous as venom can crystallise within the fang of a dead snake and remain potent for years. Do not touch the fangs of even very dead snakes, such as stuffed cobras. Details of snake bite and first aid procedures can be found at our Living with Wildlife web page.
Snakes are capable of eating prey larger than their heads. This is a handy skill to have as they do not have any means of dismembering their food. The skulls of snakes have some remarkable adaptations which assist in getting large objects down their throats. For starters, snakes skulls are constructed of at least nine separate bones. Our skulls, by comparison, are made up of only the lower jaw and the skull (ignoring the bones of the ear). The toothed lower jawbones of snakes can work independently because they are only loosly attached to each other by an elastic ligament. This allows the lower part of the mouth to stretch remarkably. The mandibles in the upper jaw (the fangs and a small number of smaller teeth are on these bones) are also capable of independant movement. By moving the mandibles snakes can "walk" their prey into the mouth, using the recurved palatal teeth fixed to the roof of the mouth like a ratchet by holding the prey in place. Snakes do not have a sternum, the ribs being hinged at their base and joined at the tips by ligaments, allowing the passage of very large prey into the gut. To allow the snake to breathe when swallowing large prey, the reinforced windpipe is pushed forward to the front of the lower jaw whilst feeding. There are tremendous advantages in being able to consume large meals. Well fed snakes can (and do) go for many months without feeding.
Snakes shed the outer layer of skin (a process known as sloughing) in a single piece, unlike mammals who are continuously shedding skin cells. (Most household dust is made up of the sloughed skin of humans!) The hardened outer layer of snake skin is quite tough to withstand abrasion endured while moving, resisting the attacks of external parasites and preventing water loss through dehydration. Sloughing is a hazardous time for snakes. As they prepare to slough a milky liquid is secreted under the outer layer of the skin to seperate the old skin from the new. Snakes have a protective scale over each eye and their vision is limited at this time as the eye becomes cloudy. They become vulnerable to predators so prior to sloughing they need to find a warm, sheltered spot. Snakes slough their skins periodically throughout their lives.
Fact and not fiction
- The forked tongue is not poisonous but is actually a chemical brush used to transfer molecules to the Jacobson's organ in the roof of the mouth, where the snakes sense of taste and smell is located. A widely forked tongue increases the ability of a snake to track its prey.
- Snakes do not have ears and cannot hear sound. Instead they detect sound by sensing vibrations passing through the ground.
- Snakes' skin is not slimy and normally it is dry.
- Snakes are not attracted to milk beyond the fact that it is wet and easy to find by smell.
- The venom toxicity of a juvenile snake is the same as that of an adult although they usually produce less venom.
- Less than 10% of newborn snakes survive to adulthood. Most are eaten by predators, such as birds or feral cats, or are killed by humans.
- In reality the danger presented by snakes is not nearly as great as perceived. Sporting accidents, dog attacks, lightning strikes and even peanuts cause more human deaths in Australia than snakebite.
- In Tasmania the presence of the blue-tongued skink (lizard) is no indication that snakes are absent.
- Tasmanian snakes are unlikely to attack people unless they feel trapped or threatened. It is easy to mistake a snakes bluff or an attempt to reach shelter for an attack.
Whilst snakes deserve our healthy respect, many people have an overly fearful attitude towards them. Snakes rely on their venom in order to capture prey - they are loathe to use it on such a wasteful exercise as biting a person.
Most snake bites occur on the extremities. In the case of hands and lower arms, this is usually a consequence of trying to catch the snake by hand - not a wise act.
Bites on the lower legs or feet can be the result of stepping on a snake. This can occur when stepping over a log where a snake is basking on the sunlit side. Walkers should wear good walking boots and be aware of where they place their feet.
There have been no recorded deaths in Tasmania from snakebites for several decades. Far more people die from ant bites, peanuts or spouses than snakes - a point well worth contemplating next time you head out into the Tasmanian bush!