Other Invertebrates
Invertebrates are very important creatures but they are often so small and strange that we don't even think of them as animals. There are approximately 990,000 species of invertebrate currently identified equalling around 95% of all known animal species. This is not a true taxonomic group but a description that includes any animal without a backbone. The first invertebrates evolved around 600 million years ago as soft-bodied, multicellular animals, from which every animal in the world is descended. This section concentrates on the terrestrial arthropods and gastropods of the invertebrate world. All invertebrates are cold-blooded (ectothermic).
An example of an invertebrate at the Isle of Wight Zoo is the Giant East African Land Snail.
Giant East African Land Snail (Achinata fulica)
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Introduction
Distribution
Habitat
Diet
size
Lifespan
Reproduction
Interesting Facts
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Introduction
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Snails belong to the class (group) gastropoda, which means 'stomach-foot' in Greek, because they crawl on their bellies and their mouth is on their foot. Gastropods include slugs and snails. These animals are invertebrates; they have soft bodies with no internal skeleton. They have a muscular slimy foot, 2 pairs of antennae, simple eyes called occelli and a hard shell for protection from predators and to prevent them drying out. Their mouth is called a radula and is located at the front of their foot. It scrapes at plant material like a cheese grater. They also feed on decaying animal matter such as bones to gain the calcium needed to grow their shell. The shell grows continuously and the oldest part is at the tip. You cannot pull a snail out of its shell without killing it.
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Distribution
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Eastern sub-saharan Africa
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Habitat
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Tropical rainforest
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Diet
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Leaves, flowers, fruit and decaying animal matter.
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Size
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Shell length: Up to 10cm (4 inches)
Body length: Up to 20cm (8 inches)
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Lifespan
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Up to 10 years
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Reproduction
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Some snails are hermaphrodites, meaning that they have both male and female organs. They cannot fertilise themselves and have to find a mate to reproduce with. Up to 50 round white eggs, 5-6mm in diameter are laid under the soil. They hatch after about 2 months.
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Interesting Facts
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Tiger snails (Achatina achatina) are the largest land snails and can grow a shell up to 28 cm (11 inches) long and have a body of up to 40cm (16 inches) long.
It is illegal to keep giant African land snails as pets in the USA as they invade farmland and destroy crops.
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