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IntroductionThe Hairy-nosed Otter Lutra sumatrana is a little-known resident of South-east Asia. Standard sources describe its range as southern Thailand, Cambodia, southern Vietnam, peninsular Malaysia, Borneo, Sumatra and associated islands (Pocock, 1941; Medway, 1978; Corbet and Hill, 1992; Wozencraft, 2005). Some sources also list Java (Lekagul and McNeely, 1977; Payne et al., 1985; Foster-Turley et al., 1990), although we know of no primary record from the island, and one lists Laos (Foster-Turley et al., 1990: 111, but contra p. 58). Although the species has been predicted to be a possible inhabitant in Laos (Deuve, 1972; Duckworth et al., 1999), there is no published record from that country and we know of no unpublished indications. Surprisingly, given the proximity of southernmost Myanmar (= Burma) to the known Thai range, there has been little published speculation of the species’s occurrence there: all that we have traced is the coding on a range map in Foster-Turley et al. (1990: 63) of “no information”, the implication being that the species can be expected potentially to occur, or to have occurred, in the country. The species is currently internationally red-listed as Data Deficient (IUCN, 2007). There were very few records of the species during the 1970s–1980s, and Foster-Turley et al. (1990) wrote that “the distribution of this species is very poorly known, and it is thought to have disappeared from wide areas where it was formerly recorded”. This grim assessment has been borne out by the subsequent very few records. Tiny relict populations have recently been discovered in south Thailand (Kanchanasaka, 2001) and at three sites in the Mekong delta of Vietnam (Nguyen Xuan Dang et al., 2001; Reuther 2003). There are a number of records from Cambodia but little information on distribution or population (Poole, 2003). Records from peninsular Malaysia in 1991 and 1994 were the first since the 1960s (Sebastian, 1995) and the species was rediscovered in Sumatra in 2005 (Lubis, 2005). All these recent authors have testified to the species’s current rarity; it is, for example, listed as nationally Critically Endangered in Thailand (Nabhitabhata and Chanard, 2005). There is little or no recent published information on the current status in Borneo, where past records (Payne et al., 1985; Kool and Yakup Nawi, 2005) indicate a wide distribution, at least formerly. While consolidating information on the carnivore holdings in the Natural History Museum, South Kensington, London (NHM), D.M.H. noticed a specimen of L. sumatrana from northern Myanmar, which has remained unpublished under this name: it had been initially identified as Eurasian Otter Lutra lutra. Given the current timely resurgence of interest in the species, and the great expansion of known geographic range that this specimen provides, we here place it on record. THE SPECIMENThe specimen, BMNH 50.587, was collected at Gam Majaw, in today’s Kachin state, Myanmar, on 6 April 1939 by Ronald Kaulback (personal collection number 712). Assigned to this site in the field were co-ordinates of 26°43′N, 97°58′E and an altitude of 3000′ (c.900 m). A male, it had been “shot and skinned by native [and taken from a] large jungle stream”. There are no measurements, nor was the skull preserved. The Kaulback collection, which contains much vital material (e.g. the most impressive series of the little-known Stripe-backed Weasel Mustela strigidorsa from anywhere in the world; Abramov et al., in press) has never been written up as a whole, although the primates and carnivore specimens were referred to in Pocock (1941). We have not traced a collector’s log from Kaulback in NHM, but the written correspondence between R. I. Pocock and Kaulback (and some between Pocock and Kaulback’s mother) are on file, and give background to the specimens. In August–September 1933, Kaulback had passed through this part of Myanmar, returning from a biological expedition in Tibet in winter 1932–1933 where he had been the map-maker (Kaulback, 1934). A few incidental mammals were collected, and Pocock urged Kaulback to return to the area and collect more, specifically requesting Carnivora “of all sorts from Tigers and Bears to small Cats and Weasels”. It seems, from the letters, that Kaulback’s return to the area, from mid 1938, had objectives additional to the collection of mammals (he was able to spend only three days per week hunting, and referred to apparently external factors setting his duration in northern Myanmar). The Second World War terminated his visit, intended to last until the end of 1940, in late 1939. In October 2007 the specimen was carefully investigated for both identity and provenance. IDENTIFICATIONMost of the rhinarium retains hair, to an extent comparable to the other (n = 11) skin specimens of the species at NHM. On this feature alone, even though many hairs seem to have been lost, the specimen is readily distinguished as a Hairy-nosed Otter from the other three species of otter in Asia (Smooth-coated Otter Lutrogale perspicillata, Eurasian Otter and Oriental Small-clawed Otter Aonyx cinerea). Most of the specimen’s pelage is rich dark brown, similar to other Hairy-nosed Otters, whereas the other three species are colder in tone. All Asian otters have a pale area on the foreneck, extending to a greater or lesser extent back through the venter. The Gam Majaw specimen has a restricted pale brown foreneck, diffusely demarcated from the darker pelage. The upper lip is extensively pale, up to a line from the nose pad to the eye. The foreneck pattern is not typical of Hairy-nosed Otter, which usually has a patch creamy- or even off-white, relatively sharply demarcated from the surrounding brown and often rather irregular in outline (e.g. Lubis, 2005: Fig. 1). However, the specimen is more similar to other specimens of Hairy-nosed Otter held at NHM in this respect than it is to any specimen of the other species, and other Hairy-nosed Otters have been documented with a similar pattern, e.g. Poole (2003: fig. 3). The pelt (including the whiskers) may have been darkened by the smoking of the skin (presumably for drying it). The other otter collected the same day at Gam Majaw, a Small-clawed Otter (BMNH 50.593), is far darker than it would have been in nature, and has singed muzzle hair and vibrissae. Pocock (1941) listed this skin as “Lutra lutra subsp.?” stating that its fur (which would be atypically dark for L. lutra) was “artificially discoloured, apparently by smoke, which blackened the throat”. He was preparing his book under time pressure during the war years, may not have had time critically to examine all specimens which came in, and, perhaps most importantly, would have had no prior expectation of finding L. sumatrana in northern Myanmar and therefore might have confined his examination to the (easy) exclusion of Smooth-coated and Small-clawed Otters, accounting for oddities in the appearance through the unusual smoke-darkening so instantly apparent on the companion specimen of Small-clawed Otter. PROVENANCEThe specimen has good data and is part of a large batch, allowing firm deductions over the likelihood of the origin being as stated. Kaulback provided excellent specimen tags, giving site, co-ordinates, altitude, date, origin and field collector’s number, in his own hand (verified by comparison with his signature on his letters). The specimen has Kaulback’s label, itself a pre-printed NHM tag, and a second label added by the NHM when the skins were catalogued in 1950. Hand-writing on the field tag is original, except the NHM specimen number. There is no taxonomic identification on the field tag, but the NHM label has “Lutra lutra” added, at a different time from the basic information; the ink and hand look the same as that of the specimen number, “50.587”. Kaulback generally left the identification blank on his tags, and this specimen’s field tag is absolutely typical of the series. Kaulback visited only far northern Myanmar on this trip, and NHM holds no specimens from him, which demonstrably originated from anywhere else. There seems no possibility that he collected this otter elsewhere and somehow muddled it with a specimen of another species from Gam Majaw. Pocock (1941) examined the specimens as each batch came in, and referred to a specimen of Lutra with an unusually dark throat from Gam Majaw. The collection lacks any other Lutra specimen from Gam Majaw, so an inadvertent label substitution after arrival at the museum but before formal cataloguing is unlikely. That this specimen came, already prepared, from a local hunter does, however, raise a potential question mark over its origin. There is now a rapacious trade in wild mammals from Myanmar into China (e.g. Rabinowitz and Saw Tun Khaing, 1998; Davidson, 1999; Martin and Redford, 2000; Shepherd and Nijman, 2007). Trade routes are poorly resolved in Myanmar, but elsewhere in South-east Asia China-bound wildlife travels huge distances, often crossing multiple international borders (e.g. Nooren and Claridge, 2001; Bell et al., 2004; Karesh et al., 2005). However, it seems inconceivable that a specimen from a remote location in far northern Myanmar in 1939 came from far away. Then, no international laws or treaties drove a clandestine trade route through remote areas, and northern Myanmar is not on any practical route from known Hairy-nosed Otter range to China. There were already sizeable wildlife markets in southern China (e.g. Mell, 1922) but contemporary narratives (e.g. Stanford, 1946) give no suggestion of a bulk, long-distance, route through Myanmar. An otter skin in possession of a rural hunter at this time and place must have been hunted locally. Kaulback found hunting very challenging in the area, and in order to amass specimens, procured them widely from local hunters: all his Stripe-backed Weasels (six skins), Yellow-bellied Weasels M. kathiah (five) and other otters (two L. lutra, two Lutrogale and seven Aonyx) were procured, skinned and presented by local hunters. We found no other Kaulback specimens that would suggest non-local origin, i.e. species that do not occur in north Myanmar or, for species showing prominent geographic variation (e.g. various civets), specimens of races inhabiting areas other than north Myanmar. A full analysis of the Kaulback specimens has not yet been made, however, although one is certainly warranted. THE GAM MAJAW AREAKaulback recorded latitude and longitude meticulously, giving his four Stripe-backed Weasels from the river Nam Tamai different, specimen-specific, co-ordinates. Hence, it is unlikely that the specimen originated more than a day’s walk from Gam Majaw. The given co-ordinates are only a few miles from the Mali Hka stream, on a ridge above the smaller Hkrang Hka stream. The area is evergreen forest on rugged terrain and, although the Mali Hka is a big stream, there is no flood-plain or swamp-land. A recent visit to the area about ten miles to the north (Khaunglanhpu) found some otter signs, although hunting in the area is doubtless high (Than Zaw et al., 2008; Zaw Win and Saw Htoo Tha Po, in litt., 2007). The area apparently remains well forested (image on Google earth, viewed on 12 December 2007). The given altitude is probably reliable: discussions were evidently held with hunters about each specimen, because annotations on the back of field tags describe habitat and collection method. A Stripe-backed Weasel from Gam Majaw on the same day is, for example, has a given altitude of 4000′, while both the day’s otters have an altitude of 3000′. SIGNIFICANCE OF THE RECORDThis record lies c.1800 km from the conventionally accepted geographic range of Hairy-nosed Otter, and occurrence in northern Myanmar contrasts with currently known habitat use in mainland South-east Asia: peat-swamp forest (peninsular Malaysia; Sebastian, 1995); Melaleuca and evergreen swamp forests (Phru Toa Daeng, southern Thailand; Kanchanasaka 2001); and Melaleuca swamp forest with flooded grasslands (U Minh, Vietnam; Nguyen Xuan Dang et al., 2001). Recent Cambodian records, all of animals in captivity or trade, plausibly come from the level lowlands with inundated forests around the Great Lake of Tonle Sap and adjacent coastal plain (Poole, 2003). The recent road-kill in Sumatra was from flooded swamp forest (Lubis, 2005). Historical Vietnam records lack habitat information; there are only three, from two regions (Thomas, 1928), despite Delacour’s (1940) statement that the species was “probably common” in central Annam. Two 1977 records came from provinces in the Mekong delta (Nguyen Xuan Dang et al., 2001), which comprise entirely level lowlands, extensively seasonally inundated. Thus, wildlife surveyors and conservationists currently active in South-east Asia perceive Hairy-nosed Otter as a species of lowland plains, often coastal areas, and especially swamp forests (e.g. Poole, 2003), although records suggest use of interior, hill, habitats in at least Borneo (Medway, 1977; Payne et al., 1985; H. Sasaki, in litt., 2007). The record from Gam Majaw indicates occurrence in rugged mid-altitude hill forest, far from lowland plains, and begs the question why the species would not be widespread across mainland South-east Asia. There are so few historical otter records for Laos, Vietnam and Cambodia that absence of records does not imply a historical absence of the species, but there are enough otter specimens from Thailand and Myanmar to suggest that Hairy-nosed Otter was genuinely not widespread in these countries. There have also been unpublished reports that around 2003 a foreign visitor to the museum of natural history at the Yangon zoo saw an old specimen of Hairy-nosed Otter. A June 2007 examination of all otter specimens at Yangon Zoological Gardens (one stuffed mount on public display and four skins in the private collection) found no Hairy-nosed Otter. The zoo staff explained that specimens that have deteriorated severely are thrown away at an annual stock-check, so it cannot be excluded that previously there was a Hairy-nosed Otter specimen there. A specimen at this zoo would not of itself indicate a Myanmar origin: the museum contained various specimens of other small carnivore species that do not occur in Myanmar. CONSERVATION CONSIDERATIONS It will never be possible to establish Hairy-nosed Otter’s pre-exploitation mainland range. Otter populations are under rapid decline almost across mainland South-east Asia, through trade-driven hunting. Field records are now rare (e.g. Duckworth, 1997; Roberton, 2007; Than Zaw et al., 2008) and animals (or their parts) move huge distances in trade. Resurveys in 2003–2007 of several parts of Laos surveyed in the mid 1990s show major declines in otters (e.g. Timmins and Robichaud, 2005), and recent surveys of rivers and associated pools found minimal otter populations in north-east Cambodia (Timmins and Men Soryun, 1998) and northern Laos (the Nam Ou; W. G. Robichaud, verbally, 2004). Otters were considered in recent national-level analyses of small carnivores in Vietnam and Myanmar to be the most severely threatened species (Roberton, 2007; Than Zaw et al., 2008), and Poole (2003) expressed grave concern for their future in Cambodia. Regional extinction of one or more otter species in South-east Asia is a real possibility. Several areas of Myanmar could, on the basis of remaining habitat, potentially support large otter populations, although uncertainty over Hairy-nosed Otter habitat use makes it unclear, which, if any, might support the species. The large Hukaung valley lies west of Gam Majaw, and supports impressive populations of other trade-threatened animals such as Tiger Panthera tigris (Lynam et al., 2006, in press). Its extensive network of streams and pools on gentle terrain at 180–320 m might, on current information, be ideal for Hairy-nosed Otter. A large conservation area, the Hukaung Wildlife Sanctuary (6300 km²), was declared in 2004 and a gigantic extension (potentially up to 15,250 km²) is under consideration (Lynam et al., in press). However, otters are almost eradicated from the area (Than Zaw et al., 2008) which faces massive hunting pressure and large-scale habitat conversion. Lower down the Chindwin catchment, the Htamanthi area of forested rivers on plains may still hold relatively good otter numbers (Rabinowitz et al., 1995; Than Zaw et al., 2008), but is scheduled soon to be inundated by a large dam (Su Su et al., in prep.). More conventional Hairy-nosed Otter habitat probably occurs in the Irrawaddy delta, close to the known range in Thailand. Otters remain unsurveyed in this area, which holds relict populations of much-declined species such as Estuarine Crocodile Crocodylus porosus (Thorbjarnarson et al., 2006), so might well also hold otters. These areas warrant priority action to conserve otter habitats, reduce hunting and explode wildlife trade networks. ACKNOWLEDGMENTS - Information on the current status of habitat around Gam Majaw was provided by Zaw Win and Rob Tizard. Scott Roberton and Hiroshi Sasaki independently concur with the specimen’s identity being Hairy-nosed Otter. Colin Poole, Hiroshi Sasaki and Annette Olsson provided comments on an earlier draft of the MS. The Wildlife Conservation Society Myanmar Programme provided the Myanmar-language abstract and arranged the visit to the Yangon Zoological Gardens: Daw Naw Htoo Phaw and U Paw Than at the gardens’ natural history museum assisted our examination of otter specimens held there. REFERENCES Résumé : Un spécimen
de loutre de Sumatra (Lutra sumatrana) aux confins de la région
nord du Myanmar Resumen: Un ejemplar
de nutria de Sumatra Lutra sumatrana del norte de Myanmar |
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