Death adder
| Death adder | ||||||||||||
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Acanthophis laevis |
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| Scientific name | ||||||||||||
| Acanthophis | ||||||||||||
| Daudin , 1803 |
The death adder ( Acanthophis ) is a genus of poisonous snakes , which is distributed with nine species in Australia and New Guinea .
features
Generally speaking, the death adders have a stocky and compact body shape with a short tail and a short, angular head, so they are very similar to a typical viper . Other characteristics that also apply to many vipers are the scales that are slightly or severely keeled, larger and erect scales above the eye, and vertical and oval-shaped pupils. In general, the venomous fangs of the venomous snakes are relatively short and immobile, whereas the dead otters have comparatively long and flexible fangs. Despite the enormous similarities to the vipers, they are real poisonous snakes. The body of all species is camouflaged and is partly drawn by crossbars, dots and bands that stand out from the basic color. The tip of the tail is flattened and can be colored in a high contrast. Depending on the species, death otters reach a total length of between 30 and 100 cm.
Occurrence
The distribution area of the death adder stretches over most of Australia , New Guinea and the east of the Indonesian archipelago. Overall, they colonize diverse habitats, the palette ranges from sand, stone, scree and semi-deserts to sparse trees, cultivated gardens and plantations to tropical rainforests . In the mountains, some species penetrate at heights of over 1,800 meters above sea level . Often death otters can be seen in close proximity to human dwellings.
Way of life
Death otters are crepuscular and nocturnal. During the day they stay very hidden, although different hiding places come into consideration depending on the habitat. You can find them between dried up grass, bulbs, bushes and roots, under tree trunks, stones and in the garden or on plantations and farms, for example in barns, under metal sheets or in other, shady, cool places. Before they become active at night and go looking for food, they can occasionally be observed in the evening when they warm up again for the night in the last rays of the sun. Death otters are ground-dwelling snakes. The term "death otter" is to be interpreted as a wrong translation. The early settlers referred to the snakes as "deaf adder", which literally means "deaf otters" and is related to the behavior, since the death otters, in contrast to many other Australian snakes, remained when approaching and did not flee, it was assumed that the Snakes are deaf. Today it is known that no snake can perceive sound from the air, but can perceive vibrations from the ground. Still, the bite of all species of death adder can be fatal.
nutrition
Death otters have developed an interesting strategy for attracting prey. Their tail tip is flattened and in some species, in contrast to the camouflaging body, colored brightly. In order to attract prey, it wiggles the tip of its tail back and forth in order to imitate a worm or something similar, i.e. a potential prey for agamas and other reptiles or birds. If a death otter lies on a suitable surface, an agame only perceives the tip of the snake's tail. This method is unique among poisonous snakes. If the animal has fallen for the trick and tries to get the apparent worm, the death otter snaps. It injects its venom to paralyze the prey and then swallow it in one piece. Death otters are also actively searching for prey. Their range of prey includes small mammals such as house mice , frogs and, above all, all kinds of lizards .
Reproduction
Like many northern Australian poisonous snakes, the death snakes are also egg-bearing ( ovoviviparous ), which means that eggs are formed, but the young snakes hatch from the thin egg shells in the womb. Depending on the species, the size of the litter can be between 10 and 20 young snakes. In captivity, the life expectancy of the death adder is around ten years; in nature this age is probably not reached.
Snake venom
Due to the strong and fast-acting venom and the inertia of the death adder, they are responsible for a high proportion of serious snakebites in Australia. Above all, the postsynaptic neurotoxin of the 80 centimeter long death adder ( Acanthophis antarcticus ) is extremely effective and around 50 percent of untreated bites are also fatal for humans due to the induced respiratory paralysis . The lethal dose is on average 0.4 mg per kilogram of body weight for a mouse. Up until a few decades ago, many people died every year as a result of bites by death snakes, and since the existence of effective antidotes, the number of deaths after a bite has fallen sharply. In addition to special antisera, treatment with drugs such as neostigmine is also possible, and breathing must also be artificially supported.
species
The following 9 types are recorded:
- Acanthophis antarcticus ( Shaw & Nodder , 1802)
- Acanthophis ceramensis ( Shaw & Günther , 1863)
- Acanthophis cryptamydros Maddock , Ellis , Doughty , Smith & Wüster , 2015
- Acanthophis hawkei Wells & Wellington , 1985
- Acanthophis laevis Macleay , 1878
- Acanthophis praelongus Ramsay , 1877
- Acanthophis pyrrhus Boulenger , 1898
- Acanthophis rugosus Loveridge , 1948
- Acanthophis wellsi Hoser , 1998
literature
- Mark O'Shea: Venomous snakes. All species in the world in their habitats. Franckh-Kosmos Verlag, Stuttgart 2006, ISBN 3-440-10619-5 .
- Keyword "Acanthophis" In: Herder-Lexikon der Biologie. Spektrum Akademischer Verlag GmbH, Heidelberg 2003, ISBN 3-8274-0354-5 .
Web links
- Toxicological Department, Rechts der Isar Clinic, Munich: Acathophis spp.
Individual evidence
- ^ ITIS Standard Report Page: Acanthophis
- ^ Acanthophis in The Reptile Database
- ↑ Simon T. Maddock, Ryan J. Ellis, Paul Doughty, Lawrence A. Smith, Wolfgang Wüster: A New Species of Death Adder (Acanthophis: Serpentes: Elapidae) from north-western Australia. In: Zootaxa . Volume 4007, No. 3, 2015, pp. 301–326, doi: 10.11646 / zootaxa.4007.3.1 .