The Possibility of Naturalisation of the African Giant ( Cricetomys gambianus , Waterhouse 1840) in the Caribbean Ross G. Cooper Cooper, R.G. 2006. The Possibility of Naturalisation of the African Giant Rat ( Cricetomys gambianus , Waterhouse 1840) in the Caribbean. Living World, Journal of The Trinidad and Tobago Field Naturalists’ Club , 2006, 54-55. 54 Living World, J. Trinidad and Tobago Field Naturalists’ Club, 2006 The Possibility of Naturalisation of the African Giant Rat (Cricetomys gambianus, Waterhouse 1840) in the Caribbean

The African giant rat or the Gambian , Cricetomys gambianus [Rodentia: ] is the world’s largest nocturnal rat and native to Africa, many thriving in urban settings. Notes on the behaviour and domestication of this rat have been published (Cooper 1998, 1999, 2000). Females normally produce four litters every nine months with up to six pups in each litter (Cooper 2000). Studies have shown that the rat is physiologically adapted to burrowing habits within cool environments (Knight 1988). The African giant rat, being predominantly vege- (Photo courtesy: Mr. A. Bickers) tarian, can be destructive to vegetable gardens and will Cricetomys gambianus, female, aged 2 yr and 9 months, weighing 1.5 kg; 95 cm long from tip of nose to tip of tail. readily eat fruits and bulbs, and is particularly fond of avocado pears, mangoes and guavas (Smithers 1975). Vegetable items, oil-palm nuts and kernels, , and its white-tipped tail and size. The original docking ports vertebrate flesh and scales have been found in the guts for the ships, however, are unknown and would need to of this rat (Iwuala et al. 1980). Growth performance of be established. Additionally, the current population of these is high with protein intake of 13% (Ajayi this rat in the Caribbean must be investigated. and Tewe 1978). The Caribbean provides a nutritionally It is therefore advocated that appropriate screening ideal habitat for this . procedures be set up to monitor the possible naturalisation This rat is highly intelligent and it has been used of this species in the Caribbean. The establishment of extensively to sniff out mines in former war-torn countries strict protocols for the carriage of exotic pets on boats (Mott 2004). There has also been a growing interest in entering Caribbean ports should be enforced. Residents keeping the rat as an exotic pet, hence facilitating its in the Caribbean wishing to keep this rat as a pet should widespread distribution. Some have inevitably escaped be required to have a licence, which ensures proper and established themselves on the Grassy Key in Florida vaccination and housing requirements. and scientists are concerned that they may compete with native species, carry diseases and damage the bird population by eating eggs (Epperson 2005). They could REFERENCES Ajayi, S. S. and Tewe, O. O. 1978. Performance of the African easily interfere with bird nests, as they are particularly giant rat (Cricetomys gambianus, Waterhouse) on commercial good tree climbers (Cooper 1998). Others have discussed rations and varying dietary protein levels. Laboratory , the possible spread of diseases like Angiostrongylus 12 (2): 109-112. cantonensis, the rat lungworm which has been detected Cooper, R. G. 1998. Giant in Zimbabwe – a short note. in the Caribbean (Prociv et al. 2000; Sithithaworn et Available at: http://www.altpet.net/rodents/cricetomys/gprat4. al. 1991). Some articles suggest that the emergence of html Human in the U.S.A. is due to rodents (Di Cooper, R. G. 1999. Some important points in the housing, Giulio and Eckburg 2004). A Rickettsiale Grahamella handling and feeding of the African giant rat. Available at: kaniae has been found in giant rat blood (Gretillat et al. http://www.altpet.net/rodents/cricetomys/gprat5.html 1981). Cooper, R. G. 2000. Giant rat in Zimbabwe. Rat and Mouse Gazette, 6 (1): 26. Shipping has facilitated the apparent introduction of Di Giulio, D. B. and Eckburg, P. B. 2004. Human monkey- this species into the Caribbean. Given favourable climatic pox: an emerging zoonosis. Lancet Infectious Diseases, 4 (1): conditions, vegetation and habitat in the islands, the rat 15-25. has the potential of rapidly reproducing and encroaching Epperson, J. 2005. Large African Rats Invading U.S. on the natural flora and fauna, including marine and Available at: http://www.redorbit.com/news/science/115896/ coastal habitats. Discussions with fishermen in Port of large_african_rats_invading_us/ Spain, Trinidad, have revealed that the giant rat has indeed Gretillat, S., Mattei, X. and Marchand, B. 1981. [A new been seen on ships and boats (Cooper 2005/6 – personal Rickettsiale of Gambia rats (Cricetomys gambianus) in observation). They characteristically identify the rat by : Grahamella kaniae n. sp. (Bartonellacae). [Article in Nature Notes 55

French]. Revue d’élevage et de médecine vétérinaire des pays 1991. Transmission of Angiostrongylus cantonensis through tropicaux, 34 (4): 383-389. the giant African snail Achatina fulica: an experimental study. Iwuala, M. O., Braide, E. I. and Maduka, N. 1980. Obser- Southeast Asian J. of Trop. Med. and Public Health, 22 Suppl.: vations on the food habits of some African rodents. Revista de 200-205. biología tropical, 28 (2): 227-236. Smithers, R. H. N. 1975. Guide to the Rats and Mice of Knight, M. H. 1988. Thermoregulation in the largest African Rhodesia. Salisbury, Rhodesia: Trustees of the National cricetid, the giant rat Cricetomys gambianus. Comparative Museums and Monuments of Rhodesia. 50 p. biochemistry and physiology. A Comparative physiology, 89 (4): 705-708. Ross G. Cooper Mott, M. 2004. Bees, Giant African Rats used to Sniff Physiology Division, Faculty of Health, Landmines. Available at: http://news.nationalgeographic.com/ University of Central England, news/2004/02/0210_040210_minerats.html Prociv, P., Spratt, D. M. and Carlisle, M. S. 2000. Neuro- Baker Building, Room 701, angiostrongyliasis: unresolved issues. International Journal of Franchise Street, Perry Barr, Parasitology, 30 (12-13): 1295-1303. Birmingham B42 2SU, U.K. Sithithaworn, P., Brockelman, W. Y. and Brockelman, C. E-mail: [email protected]

Web Height as a Niche Separator in Two Antillean Orb-weaving Spiders

Choice of foraging site is a critical decision for any Leucauge sp. (Tetragnathidae) and Gasteracantha sit-and-wait predator. For web-building spiders, which cancriformis (Araneidae) are widepread orb-weavers must invest heavily in spinning a web, this decision may which are locally abundant in the Antilles (pers. obs.). be a semi-permanent one. Accordingly, we expect a In January, 2006 we found Leucauge sp. in abundance in given species to have fairly characteristic web and web- gardens, open areas and lowland forests on Nevis, Lesser site features. In a comparison of several web parameters Antilles. On the same island G. cancriformis was common in nine orb-weaving species in Ghana, including one only in open areas, especially at the edges of secondary Gasteracantha sp. and one Leucauge sp., Edmunds and forest, where it was interspersed with Leucauge sp. Edmunds (2001) found that each species-pair could Although the two species differ in size – G. be separated according to at least one parameter. Our cancriformis is strongly sexually dimorphic, so that purpose here is to consider just one parameter, height females are larger than those of Leucauge sp., while above the ground. males are smaller than Leucauge sp. males – their webs 25

20

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10 Frequency

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0 20 60 100 140 180 220 260 300 340 380 >400 Height above the ground (cm) Fig. 1. Frequency of web heights of 71 female Leucauge sp. (black bars) and 80 female Gasteracantha cancriformis (white bars) in open areas near Gingerland, Nevis. The height of the hub is estimated to the nearest 20 cm.