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Giant Orange Killer Snail
Other common names: Giant Carnivorous Snail, Giant Alligator
Snail,
Devil's
Snail, Orange Predator Snail
Latin name: Euglandina giganteus
Origin: rainforest of Tasmania
Date: circa 1746 AD
Size: 11.5 x 3.5 x 3 inch
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Description of the
specimen: Carnivorous snails are important and deadly predators
found in the rainforest of Tasmania. Over 30 species of
carnivorous snails were identified. They vary in size from a
less than 1" to over 12” long. The adults of most species are
green, red, or brown and somewhat thick. A few are an iridescent
red or green. They are commonly found under leaves or debris.
Some species also climb into trees, shrubs, and crop plants
looking for prey. Killer snails move quickly when attacking a
prey or being disturbed. Most of the killer snails emit a strong
smelling irritant or toxic mist to paralyze their preys. Some of
the killer snails can also sting using nematocysts, tiny
stinging cells that line the front end the animal. When the
snail touches the prey, the nematocysts fire, puncture the
victim and eject venom. The venom paralyzes and kills the snail’s
prey. The venom of some killer snails can be deadly to humans as
well. Only box jelly fish shares the same mechanism and venon to
attack preys in the animal world. The venon could causes heart
failure and death within minutes. The adults are fierce
predators that chew up their prey with their large, sharp
mouthparts. Caterpillars, grubs and beetles, fly maggots and
pupae, earthworms, fish, frogs, small birds and even wild mice
are common prey for many species of killer snails. They can
consume their body weight in food daily. Many are nocturnal and
some are attracted to lights at night.
All the killer snails found in Tasmania is hermaphroditic
(having both male and female reproductive organs). Although this
means that in theory they can mate with themselves, they hardly
do this in nature. As long as there are other snails around,
they will always mate with another individual. Killer snails
just like common snails have an extensive mating ritual which
involves circling around, and then riding up to each other. They
touch each other with their foot, tentacles and genital organs.
This takes usually about an hour, the actual mating can easily
last eight hours. Each snail has two sets of sex organs. One
with a penis, testes and sperm and the other with ovaries, eggs,
an oviduct and a pouch or receptacle for storing sperm of
another snail. The penis is located at the base of the right
tentacle, close to the vagina. In some species, like Euglandina
concavum, little chalky darts or love darts are shot into each
others bodies. This doesn't happen always however. Recent
research (Koene and Schulenburg 2004) has shown that an
allohormone in the mucus on the dart makes digestion of the
sperm cells more difficult. This way more sperm cells can reach
the spermathecae. The sperm is transferred in so-called
spermatophores which are exchanged between the snails. After
about two weeks the eggs are laid, although in some species, the
seminal fluid can be stored for up to year. The eggs look like
little white pearls and are laid seperatly or in groups under
stones, logs or fallen leafs. After a few weeks tiny snails are
born. They have a transparent shell. Some snail species are
ovo-viviparious, this means that the eggs hatch inside of the
snail, and tiny snails are born. Most species reach maturity in
a year,but the larger ones can take two to four years to reach
maturity.
Takeshi Yamada
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