By N. Sivasothi
Not all wild animals are easily tamed but there is sufficient evidence to indicate that otters, when caught young, are easily tamed. Ansell (1947: 382) comments that captive Smooth Otters in Rangoon Zoo quickly became accustomed to humans. They have been kept as pets or employed for their natural predatory skills by fishermen (Cantor, 1846; Gudger, 1927; Maxwell, 1960: 158; Wayre, 1976: 103-169). It appears that L. sumatrana has been kept as a pet as well, (Cantor, 1846; Banks, 1931: 60; Wayre, 1976: 167) although the identity of the species in these accounts are in some doubt except, perhaps, for Wayre.
There are several roles that a zoo can serve by its maintenance of captive population of otters: public education, study of the biology and breeding for maintaining gene pools or for reintroduction. Public education is aided by the fact that otters have a high exhibition value due to the water acrobatics of the Lutra spp. and the fascinating land behaviour of the Small-clawed Otters A. cinereus (Timmis, 1971; Duplaix-Hall, 1972). Its role in environmental education as defined by the IUCN has been discussed by Janßen (1991).
There have been few studies of otters in captivity: Duplaix-Hall (1972, 1975), Foster-Turley (1990) (who also refers to Wright, in press), Reuther (1991) and Wayre (1976, 1989). Observations in these literature point to significant social and behavioural differences between the Asian (A. cinereus and L. perspicillata) and European (L. lutra) otters. The Asian species are social, diurnal and vocal with the male involved in raising the cubs. In the more solitary, nocturnal, quieter Lutra lutra, however, the male is generally kept away from cubs by the female. During a brief study of a family (1 male, 2 females, 1 cub) of A. cinereus in the Melaka Zoo by Nor (1990b), the male spent more time on the maintenance of the nest while the two females raised the cub. Contribution of the male toward rearing the young and tolerance by the female has also been exhibited by this species in Zoo Negara, K. L., Malaysia. Pellis (1984) gives an account of play-fighting in this species. Studies on the Smooth Otter all give mention to its fossorial nature prior to breeding (Yadav, 1967; Badham, 1973; Desai, 1974; Duplaix-Hall, 1975; Markowitz, 1982). Data compiled by Reuther (1991) suggests that the average number of cubs per litter in captive populations is three for both A. cinereus (n=90 litters; range 1-7 cubs/litter) and L. perspicillata (n=20 litters; range 1-5 cubs/litter).
Most of the studies mentioned above tend to be based on observation of sole collections in individual zoos. In countries with large collections, it is possible to collate data to form more representative conclusions. In 1988, the American Association of Zoological Parks and Aquariums (AAZPA) has taken the initiative to include the Asian Small-clawed Otter as part of its Species Survival Plan (SSP) programme. It intends to manage viable captive populations of A. cinereus in order to assist conservation in the wild, and has initiated a studbook for the species (Foster-Turley & Engfer, 1988), which is now coordinated by Dusty Lombardi of Colombus Zoo (Foster-Turley, in litt., 3 Dec 1997). Such coordinated work effectively increases the population size of otters observed, thus allowing a significant contribution from zoos. The SSP identified renal calculi as a significant health problem amongst A. cinereus in North American zoos (Foster-Turley & Engfer, 1988; see also Nelson, 1983; Calle & Robinson, 1985), which had earlier been noted at the Otter Trust (Wayre, 1989: 82). Other health problems amongst captive otters (Lancaster, 1975: 65; Rogoschik & Brandes, 1991) that might exist may be also be highlighted much earlier in this manner, and should encourage curators of collections to cooperate likewise. However, there is only one other studbook for otters, maintained for L. lutra.
The role of captive breeding in the conservation of species is an important one (Flesness & Foose, 1990), although there are arguments that it is still in an experimental stage (Cohn, 1988). The rare L. sumatrana and L. l. barang cannot be found in zoos anywhere, and there appear to be few zoos with L. perspicillata. So many zoos with otters keep A. cinereus, that it is not listed as a rare animal in the International Yearbooks Census of Rare Animals in Captivity. The data from the Yearbooks never presents the complete picture for they are limited by the response of zoo curators, but it remains the best source of information for zoos. Based on the 1988 - 1992 data, there are at least 34 zoos with the Small-clawed Otter, only two with the Smooth Otter, but at least 48 zoos with L. l. lutra (Table 1). Indeed, the Eurasian otter may well be the best known species in captivity (Reuther, 1991), although based on the studbooks, there are greater numbers of captive A. cinereus (IZY, 1992).
Besides the Yearbook data, there are evidently greater numbers of Smooth Otters in captivity, for Naidu & Malhotra (1989) reported that there were 29 animals of the species in the different Indian zoos. Apparently in 1985, there were 18. In the National Zoological Park, New Delhi, they report that 39 cubs had been born in 13 litters since 1968 (to 1988). No other information is available, since this citation is only an abstract. Sumitro et al. (1994) report that a captive Smooth Otter is kept at their collection as well, in Gelanggang Samudra Jaya Ancol in Jakarta, Indonesia.
perspicillata L. sumatrana Remarks Malaysia &
Singapore 5 2 0 Pers. obsv. in Singapore
Zoological Gardens, Night Safari, Zoo Negara (K. L.), Zoo
Melaka and Taiping Zoo; Thailand 1 1 - From photos of Bangkok Zoo,
taken by K. Lim Indonesia 2 1 - Pers. obsv. & Sumitro et
al. (1994) India ? >2 0 Naidu & Malhotra, 1989;
Not specified U. K. 15 0 0 Ironmonger, 1992; of 31
'good zoos' U. S. A. 10 0 0 Nyhuis, 1994; 21 zoos have
L. canadensis World 34 2 - Mammals bred in
captivity and multiple generation births,
International Zoo Yearbook, vols. 30 - 33 + pers. obsv.; L.
l. lutra in at least 48 zoos
L. l. barang
Malaysia & Singapore
Pers. obsv. in Singapore Zoological Gardens, Night Safari, Zoo Negara (K. L.), Zoo Melaka and Taiping Zoo;
From photos of Bangkok Zoo, taken by K. Lim
Pers. obsv. & Sumitro et al. (1994)
Naidu & Malhotra, 1989; Not specified
Ironmonger, 1992; of 31 'good zoos'
U. S. A.
Nyhuis, 1994; 21 zoos have L. canadensis
Mammals bred in captivity and multiple generation births, International Zoo Yearbook, vols. 30 - 33 + pers. obsv.; L. l. lutra in at least 48 zoos
There are five zoos in Peninsular
Malaysia and Singapore, and all maintain A. cinereus, with
only Zoo Negara maintaining a pair of Smooth Otters. Taiping Zoo has
a single Smooth Otter. The conditions of these enclosures are
acceptable, for the water:land ratio is not too high, which was a
common problem in the 1970s, leading to high mortality
(Duplaix-Hall 1972, 1975). The over-representation of the
Small-clawed Otter is, however, a problem. The captive breeding role
of zoos would be better served by seeking to establish Eurasian or
Hairy-nosed Otters in Southeast Asian zoos. This would solve the
problem of familiarising field workers with the form of an animal
which most have not seen, as well as to educate the public, most of
whom are not aware that otters may be found locally.
Species 1988 1989 1990 1991 1992 born exotic
cinereus 33 30 35 42 45 185 176 L.
perspicillata 1 1 0 L. l.
lutra 24 37 45 34 30 170 1
L. l. lutra
While it may be possible to maintain rare animals in captivity, breeding is the next problem for zoos have to attempt to breed these animals and also maintain genetic diversity, preferably by input of wild stock. It has often been mentioned that the breeding record of otters remains poor but recent statistics from the IZY seem to indicate a reasonable number of births in captivity for A. cinereus and L. lutra (Table 2). However, 95% of the Small-clawed Otter cubs were born in zoos in countries outside their natural range (exotic countries). Only seven of the 34 zoos which bred A. cinereus would have had easy access to wild populations (Table 3). Input from the wild is an important and easy way of maintaining genetic diversity. This is the case with animals in local zoos, such as Zoo Negara, which has had repeated inputs from the wild (Nazim, in litt.).
Continent IZY pers.
obsv. Total Australia/New
Zealand 4 - 4 Asia 4 3 7 Europe 13 - 13 U. S. A. 10 - 10 Total 31 3 34
U. S. A.
An important indicator of the understanding of the biology of an animal by zoos and the fitness of the captive population is the survivability of cubs. Data for A. cinereus and L. lutra is summarised in Table 4. Although survival has not been standardised, many major zoos assume this to mean 30 days or more. It is also unclear if all zoos are reporting on their survivors. Based on the data which includes reports of mortality, it appears that although more cubs of the Small-clawed Otter are born (50/year), only about three-quarter survive, whereas 94% of the fewer cubs of L. lutra born (36/year) each year survive. This is in agreement with the expectation of the observation of Reuther (1991), who states that the Eurasian Otter is perhaps the best-studied species of otter.
Year 1988 65 96 33 51 12 24 25 10 1989 60 97 30 50 12 37 38 10 1990 78 100 35 45 10 45 45 12 1991 84 92 42 50 10 34 37 9 1992 79 86 45 57 14 30 35 10 Average 73 94 37 50 34 36
One of the objectives of the IUCN/SSC Otter Specialist Group (OSG) should be to coordinate the collection of data from regional zoos in order to learn more about the biology of this poorly studied group of animals. There are several reasons for this: Firstly, most of the information about otters in captivity remain at this stage, fragmentary due to the absence of data collation. It is not even clear which zoos are present in Asia, for the IZY only obtains information from participating zoos. Smaller collections may not be responding to their queries, or may be unknown to the editors of IZY. In Peninsular Malaysia, for example, the Taiping and Melaka Zoos are not reflected in the list of Zoos and aquaria of the world (Olney & Ellis, 1993) nor IUCN publications such as Botanic and zoological gardens of the Asia-Pacific region in Collins et al. (1991).
For example, Sumitro et al. (1994) reported interbreeding between A. cinereus and L. perspicillata in captive populations in Indonesia, not previously reported on. The hybrid generation comprised of four cubs of a pair of males and females each. Apparently further attempts at hybridisation failed. No other information was provided. Subsequently, Foster-Turley and Melisch (1996) published a paper in a more accessible journal in which they explained that the interspecific breeding was discouraged by participants at the Indonesian Otter Symposium. If not for efforts of the authors, valuable information that would otherwise have been lost this way, was captured because of monitoring by members of the IUCN/SSC Otter Specialist Group.
Ansell, W. F. H., 1947. Notes on some Burmese mammals. J. Bombay Nat. Hist. Soc., 47: 379-383.
Badham, M., 1973. Breeding the Indian smooth otter, Lutrogale perspicillata sindica X L. p. perspicillata, at Twycross Zoo. IntL. Zoo Yb., 13: 145-146.
Banks, E., 1931. A popular account of the mammals of Borneo. J. Malay. Brch R. Asiat. Soc. 9(2): 60-61.
Calle, P. P. & P. T. Robinson, 1985. Glucosuria associated with renal calculi in Asian small-clawed otters. JAVMA, 187(1): 1149-1153.
Cantor, T., 1846. Catalogue of Mammalia inhabiting the Malayan Peninsula and Islands. J. Asia. Soc. Beng., 15: 171-203, 241-279.
Cohn, J. P., 1988. Captive breeding for conservation. BioScience, 38(5): 312-316.
Collins, N. M., J. A. Sayer & T. C. Whitmore, 1991. The conservation atlas of tropical forests: Asia and the Pacific. IUCN, 256pp.
Desai, J. H., 1974. Observations on the breeding habits of the Indian smooth otter, Lutrogale perspicillata, in captivity. Int. Zoo Yb., 14: 123-124.
Duplaix-Hall, N., 1972. Notes on maintaining river otters in captivity. Int. Zoo Yb., 12: 178-181.
Duplaix-Hall, N., 1975. River otters in captivity: a review. In: Martin, E. D. (ed.), Breeding endangered species in captivity. Academic Press, London: 315-327.
Flessness, N. R. & T. J. Foose, 1990. The role of captive breeding in the conservation of species. In: 1990 IUCN Red List of Threatened Animals. IUCN, Gland: xi-xv.
Foster-Turley, P. & S. Engfer, 1988. The species survival plan for the Asian Small-clawed Otter, Aonyx cinerea. Int. Zoo Yb., 27: 79-84.
Foster-Turley, P., 1990. Otters in captivity. In: Foster-Turley, P., S. Macdonald & C. Mason (eds.), 1990. Otters. An action plan for their conservation. IUCN/SSC Otter Specialist Group, Gland: 17-21.
Gudger, E. W., 1927. Fishing with the otter. The American Naturalist, 61(674): 193-225.
Ironmonger, J., 1992. The good zoo guide. HarperCollins, Lond., 208pp.
Janßen, W., 1991. The otters role in education. In C. Reuther & R. Röchert (eds), Proc. V. Intl Otter Colloq., Hankensbüttel, 1989. Habitat, 6: 323-326.
Lancaster, W. E., 1975. Exhibiting and breeding the Asian small-clawed otter, Amblonyx cinerea, at Adelaide Zoo. Int. Zoo Yb., 15: 63-65.
Markowitz, H., 1982. Behavioural enrichment in the zoo. Chp11: Exhibits for a theme park. Van Nostrad Reinhold, N. Y.: 114-131.
Maxwell, G., 1960. Ring of Bright Water. Penguin Group, Lond., 212pp.
Melisch, R & R. Foster-Turley, 1996. First record of hybridisation in otters (Lutrinae: Mammalia), between Smooth-coated Otter, Lutrogale perpspicillata (Geoffroy, 1826) and Asian Small-clawed Otter Aonyx cinerea (Illiger, 1815). Der Zoologische Garten, 66: 284-288.
Naidu, M. K. & A. K. Malhotra, 1989. Breeding biology and status of the Smooth Indian Otter (Lutra perspicillata) in captivity. IUCN/SSC Asian Otter Specialist Group Newsletter, 2: 6.
Nelson, G. H., 1983. Urinary calculi in two otters (Amblyocix sernaria). J. Zoo An. Med., 14: 72-73.
Nor, B. H. M., 1990b. Observation on the parental investment by Small-clawed Otter in captivity. J. Wildl. Natl. Parks., 9: 47- 52.
Nyhuis, A. W., 1994. The Zoo Book. A guide to Americas best. Carousel Press, CA, U. S. A. 277pp.
Olney & Ellis, 1993. Zoos and aquaria of the world. International Zoo Yearbook, 34.
Pellis, S. M., 1984. Two aspects of play-fighting in a captive group of Oriental Small-clawed Otters Ambloynx cinerea. Z. Tierpsychol., 65: 77-83.
Reuther, A., 1991. Otters in captivity - review with special reference to Lutra lutra. In C. Reuther & R. Röchert (eds), Proc. V. Intl Otter Colloq., Hankensbüttel, 1989. Habitat, 6: 269-307.
Rogoschik, B. & B. Brandes, 1991. Diseases among captive otters. In C. Reuther & R. Röchert (eds), Proc. V. Intl Otter Colloq., Hankensbüttel, 1989. Habitat, 6: 309-315.
Sumitro, P. Effendi, D. R. Seto & T. Sahir, 1994. Pemeliharan dan penegmbangbiakan berang-berang di Gelanggang Samudra Jaya Ancol. Prosiding simposium pertama mengenai berang-berang di Indonesia. PHPA/AWB-Indonesia, Bogor, Juni, 1994. 75-80.
Timmis, W. H., 1971. Observations on breeding the Oriental short-clawed otter, Amblonyx cinerea. Int. Zoo Yb., 11: 109-111.
Wayre, P., 1976. The River People. Souvenir Press, Lond., 187pp.
Wayre, P., 1989. Operation Otter. Chatto & Windus, Lond., 166pp.
Yadav, R. N., 1967. Breeding the Smooth-coated Indian otter, Lutra perspicillata, at Jaipur Zoo. Int. Zoo Yb., 7: 130-131.