Fang
Venomous fangs are special hollow fangs that venomous snakes use to inject venom into their prey. They also use the poison bite for defense. A canal in the tooth is similar to an injection needle. The exit of the poison gland opens at the base of the tooth, its poisonous secretion emerges near the tip of the tooth.
While sea snakes (family Hydrophiidae) and poisonous snakes ( Elapidae) have relatively short fangs fixed in the jaw, the fangs of vipers (Viperidae) are very long and lie in skin pockets in the palate (the tooth sheaths ) with their mouths closed . They are only "folded out" to the bite at lightning speed when the mouth is opened.
Since snakes typically strike at great speed, it can easily happen that a poisonous tooth is pulled out when bitten. Lost or blunted poisonous teeth are therefore regularly replaced by new ones, which are already preformed as “replacement teeth” in the mucous membrane.
Other animals with poison fangs
Besides the venomous snakes there are only two other poisonous reptile genera, the crusty lizards and the Komodo dragon . While the venom gland and tooth of the snakes are located on both sides in the upper jaw, they are located in the lower jaw of the crusty lizards and komodos. Their teeth are also not hollow, so that the poison secretion can be injected through them, it flows through furrows in the teeth into the wound. In order to achieve this, the crusty lizard does not let go of its prey quickly, like most poisonous snakes, but bites into it, possibly for hours. The Komodo dragon dissolves its poison in its own saliva. This enters the wound of the prey when it is bitten.
Some species of shrew , such as the domestic water shrew and the shrew- like slit weevil, have poisonous saliva that gets into the wound when it bites. However, they do not have special fangs, in contrast to the extinct species Bisonalveus browni , whose fossil remains have been found in North America. The canine teeth of this small predator had a deep groove from root to tip, similar to those of the African Boomslang , which is why it is believed that a poisonous secretion also flowed through them.
The moray eel used to be considered poisonous, but it has no fangs. Complications from moray eel bites are explained by bacterial infection .
On the other hand, the bite of the blue-ringed octopus or octopus ( Hapalochlaena ), which occurs on the coasts of Australia, Indonesia and New Guinea and releases a nerve poison with its beak-like bite tool, which is more effective than any snake poison, is very poisonous .
The jaw claws ( chelicerae ) of the arachnids are not teeth, but reshaped extremities, in their function they correspond to the venomous teeth of snakes.
literature
- Klaus Zimniok: Enchanted World of Reptiles. 1979. ISBN 3-7057-2004-X
Web links
- Poisonous, old and snappy. On: Wissenschaft.de from June 23, 2005. About the 60 million year old fossil Bisonalveus browni .
- How the snakes became poisonous. On: Wissenschaft.de from March 1, 2005. In the course of evolution, snakes have further developed their poisons from initially harmless proteins.