Otter (Lutrinae) Care Manual - Association of Zoos and Aquariums

Association of Zoos and Aquariums 84
Otter (Lutrinae) Care Manual
Asian small-clawed otter: “Small-clawed otters prefer shallow water with a good food supply and
moderate to low bank side vegetation. They demonstrate a high climatic and trophic adaptability,
occurring from tropical coastal wetlands up to mountain streams. They make use of freshwater and peat
swamp forests, rice fields, lakes, streams, reservoirs, canals, drainage ditches, rice paddies, mangroves,
tidal pools, and along the coastline. In mountainous areas, they frequent swift-flowing forest streams with
rocks and boulders. Their preferred food is crustaceans and mollusks. Across much of their range they
are sympatric with Eurasian Otters (Lutra lutra), Smooth-Coated Otters (Lutrogale perspicillata) and
Hairy-Nosed Otters (Lutra sumatrana), and there is clear evidence of niche separation between the
species.
Although the species' range appears large, in the last decade actual distribution has shrunk,
especially in the west, compared to historical records. They are currently found from the Himalayan
foothills of Himachal Pradesh eastward throughout south Asia, extending up to Philippines and down
through Indonesia. A small isolated subpopulation has been reported from southern Indian hill ranges of
Coorg (Karnataka), Ashambu, Nilgiri and Palni hills (Tamil Nadu), and some places in Kerala. They were
formerly found in Sri Lanka, but their current status there is unknown. The only areas in which these
animals are known to be common today are Peninsular Malaysia, especially in Kedah, and in the western
forests and southern marshes of Thailand.
The main threats throughout Asia are habitat destruction because of deforestation (loss of the smaller
hill streams), agriculture (especially tea and coffee plantations in India, draining of peat swamp forests,
and destruction of coastal mangroves for aquaculture), and settlement. Water courses are being polluted
with pesticides from plantations and other intensive agriculture and heavy metals, affecting the gillfeeders
on which this species depends. This interferes directly with otter physiology. Prey biomass is also
being reduced by overexploitation, and the vast aquaculture industry regards otters as pests and
persecutes them directly.
Although international and national level legal protection is in place, local legislation is needed. The
impact of protection measures on livelihoods needs to be assessed and answered. Habitat protection and
interpopulation corridors need to be established. Research on all aspects of this species biology and
ecology is needed (IUCN Otter Specialist Group).” The population is considered to be decreasing.
Giant otter: “The wild population is estimated to have a total population of 1,000 to 5,000 individuals. In
the past, giant otters were frequently hunted for their fur. This trade in giant otter pelts is one of the
primary reasons giant otters are endangered in the wild. Because this species is active during the day,
very vocal, and not afraid to approach humans, they were easy to hunt. Much of the population became
decimated until efforts were finally made to protect them in the 1970’s.
Although they still face other serious threats, habitat destruction and degradation, poaching, and
unmanaged tourism are the primary threats faced by giant otter today. The areas in South America where
the giant otter lives are rapidly being destroyed and degraded by logging, mining, exploitation of fossil
fuels and hydroelectric power (dams), river and land pollution, and over-fishing. Some giant otter cubs are
still being taken from the wild illegally to be kept as pets and they usually die in the hands of
inexperienced caretakers. Tourists can disturb giant otters when they are rearing cubs. This can have a
negative effect on how successfully parents rear their litters (IUCN Otter Specialist Group).” The
population is considered to be decreasing.
North American river otter: This species is also referred to as the Nearctic otter. However, whatever you
call it, the river otter represents a North American conservation success story. From a historic high when
their range extended throughout most of North America, river otter populations fell until:
“During the late 1800’s and early 1900’s, the synergistic effect of wetland destruction,
pollution, and overexploitation for furs was devastating to North American river otter
populations. Additional otter losses were due to road kills, accidental drowning in fishing nets
and ‛incidental take during beaver trapping’.” (Foster-Turley et al. 1990)
By the 1970’s, Nilsson & Vaughn (1978) estimated that the river otter was found in only 33% of its
former range. They listed the causes of this as intensive trapping, pollution, destruction of habitat by
clearing land, draining marshes, and channelizing streams. However, since 1976 over 4,000 otters have
been reintroduced in 21 states and provinces throughout their former North American range (including
Canada).