L197 Giant African Land Snails CONTENTS

Giant African Land Snails L197 July 2006 July 2006 L197 Giant African Land Snails CONTENTS Page 1 Introduction 1 2Housing 3 3 Diet 5 4 Handling 6 5 Sources of supply 7 6 Breeding 7 7 Disease 8 8 Health and safety 9 9 Humane killing 10 10 Appendix, including addresses of suppliers, sources of information 11 and books This Guide is a revision of L 197, originally published in April 1992. This guide combines material from the first edition of Guide L197 and information originally published in the Guidelines series by the ILEA Centre for Life Studies, hence the ‘g’ on the front cover. Following the closure of the Centre, CLEAPSS acquired the copyright of all the CLS publications. Strictly confidential – circulation to Members and Associates only © CLEAPSS® 2006 CLEAPSS Brunel University Uxbridge UB8 3PH Tel: 01895 251496 Fax: 01895 814372 E- mail: [email protected] Web site: www.cleapss.org.uk MAINTENANCE NOTES FOR THE GIANT AFRICAN LAND SNAILS (and other land snails and slugs) 1. Introduction GIANT AFRICAN In many parts of the world the giant African land snail (Achatina fulica) is LAND SNAILS a serious native or introduced pest to agriculture. As its name suggests, it is a large, land-living snail that was originally native to East Africa. There are also other species of large terrestrial snails from Africa which are now bred in the UK; Archachatina marginata and Achatina achatina originate from West Africa and are becoming increasingly common. Achatina fulica is, however, regarded as the ‘giant African land snail’, more for its notoriety than anything else. In many respects, the giant snails show few differences in appearance when compared with the snails commonly found in British gardens. They do, of course, grow to a much larger size and in general have a more pointed form to the spiral of the shell. (The world record snail is ‘Gee Geronimo’, weighing in at 900 g and measuring 39.3 cm from head to tail with a shell length of 27.3 cm!) Like all snails, they move along on a single foot. A gland at the front of the foot produces a lubricating slime over which the foot slides. The foot of the giant African land snail also spreads out further when compared with that of native species. Achatina fulica is the largest and commonest giant African land snail and, although originally from East Africa, it is now distributed throughout the tropics. It may reach maturity in captivity in just over one year but this can take four or five years in the wild. It lays small, yellowish-white eggs about 4 mm in diameter. 1 IDENTIFYING FEATURES With a shell length averaging 250 mm in adults, the snails generally weigh OF THE DIFFERENT about 250 g. The shell is a brown colour with weak, darker markings that SPECIES appear as bands across the spiral. The mantle, the fleshy part inside the shell through which the foot protrudes, is a pale yellowish colour. The columella, the smooth inner surface to the opening of the shell (see diagram), is also yellow. The ‘head’ portion of the foot is light brown but the rest of the foot is paler with thin, net-like markings. Achatina achatina grows to about 200 mm and has a much more patterned shell than A. fulica. The shell is more yellow with distinct brown jagged bands. On the shell can be seen striations that are distinctly and regularly broken. The columella is purple and the eggs are about 6 mm in diameter with a distinctly yellow colour. This species comes from West Africa, ranging from Liberia to Nigeria. Archachatina marginata is again about 200 mm when fully grown. The shell is much less pointed than the Achatina species and this ‘roundness’ is especially obvious in young animals. The columella is white and the eggs are comparatively large at 17 x 12 mm. The striations on the shell may give the appearance of a ‘woven’ texture, especially when looked at under a magnifying lens. The head is a dark grey but the rest of the foot is a lighter grey. Its range stretches from Zaire to the Ivory Coast. SNAILS AROUND THE The snail’s ability to eat virtually any form of plant material, combined WORLD with its capacity to build up large populations rapidly, means that it can be a serious agricultural pest. Indeed, in suitable habitats, the snail is able to maintain populations averaging 150 per square metre. Achatina fulica has been introduced into a number of tropical ecosystems in the Far East and Pacific islands, sometimes by accident but also deliberately. It has competed with native species of snail and reached such large numbers that predatory species of snail, such as Euglandina rosea, have been introduced, disastrously in some areas, to control the giant African snails. In Polynesia, Euglandina has attacked snails other then the giant African species and caused the extinction of dozens of species of native tree snail. In 1928, the giant African land snail was introduced into Sarawak as poultry food and, during the second world war, the Japanese forces took the snail as human food to New Guinea and other occupied territories. Related West African species are also extensively used as a food source. In Ghana, for instance, they constitute the greatest single source of animal protein. EATING GIANT In Europe and North America the snails are also eaten, but in upmarket, AFRICAN SNAILS gourmet restaurants. The traditional European species of ‘escargot’ is relatively small and slow-growing, so the demand for snail meat has been partially satisfied by the flesh of the giant African land snail, ‘Escargot achatine’. The commercial success of farming and ranching ‘Escargot achatine’ may be appreciated by the observation that as far back as 1977, over 1,500 tons of canned snail meat, worth US $3 million, were shipped to Europe from Taiwan alone. The giant substitute is said to be slightly inferior to the edible European snails as it is ‘rubbery’ and too often ‘swampy-tasting’. When highly flavoured with garlic, chopped and stuffed into the shells of genuine escargot, however, most of the people eating the African snails are effectively deceived. OTHER LAND SNAILS Although these maintenance notes have been written specifically for giant AND SLUGS African land snails, most of the essential details apply equally well to other species of terrestrial snail or slug, including native British species. Native species, however, will only thrive if they are kept in conditions below room temperature and obviously do not require a source of heat. A north-facing window sill, away from radiators, will often be suitable. 2 2. Housing Giant African land snails are most conveniently housed in aquaria or vivaria. As the tanks are not required to be watertight, aquaria that leak and are no longer suitable for fish, may be given a new lease of life. Alternatives include large plastic propagators. Some suppliers1, (including Blades Biological, Bugs Direct and Small-Life Supplies) sell snail kits, which they call starter or school kits and these consist of a container and all other items needed to keep snails for the first time. AVOID Young snails can be kept in small tanks or even troughs but, as they grow, OVERCROWDING thought should be given to the final display container for the adults. Except for short periods, do not attempt to keep more than four adults in a tank measuring 100 x 30 x 30 cm. COVERING THE TANK An escape-proof (but not air-tight) top is necessary and preferably one that allows the fitting or arrangement of a light source. A sheet of glass or Perspex, slightly raised on small pieces of plasticine, will often suffice to cover the container for small to medium specimens. Larger animals are quite strong and will require a more secure lid. Purpose-built metal tops for aquaria (with space for a light bulb fitting) are available from some specialist suppliers. A SOURCE OF HEAT The snails need to be kept warm (other than in the warm temperatures of the summer months) and the heat from a 60 watt bulb will often be ade- quate for most purposes. Additional heating may be necessary over longer holidays when school heating is turned off. A temperature between 24°C and 30°C will ensure continuous activity. If necessary, the heat from a bench or Anglepoise lamp can be directed into the tank through the top cover or sides. 60 watt basking spot lamps could be used and these are available from local pet shops or specialist suppliers selling equipment for keeping reptiles2. An alternative (possibly preferable - see below) to using a light source for warming the snails is a heating mat3 such as the Mini-Heat mat (approx. 130 x 100 cm) or the HabiStat heat mat (in various sizes). Those used in seed propagators (available from Philip Harris and the Stewart Company) could also be employed. The purchase and fitting of electrical items used to heat or light the snails’ tank should comply with any safety requirements made by the employer. Only equipment which is suitable for the intended purpose should be used and this must be safe in operation. Schools should contact CLEAPSS for advice on equipment they intend to use. SLOWER GROWTH IN Although providing heat from a light source is convenient, it does have THE LIGHT one drawback. The snails are mainly nocturnal when they feed most readily. Thus in bright light, the snails feed less and grow more slowly. A coloured lamp or a heat mat could be used, but it may be necessary to accept the snails’ reduced activity and slower growth in the light.

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