亚洲小爪水(tǎ)Asian small-clawed otter

1. 分类TaxonomyIUCN




亚洲小爪水獭Aonyx cinereusIlliger1815英文名Asian small-clawed otterOriental Small-clawed OtterSmall-clawed Otter

2. 保护级别Conservation assessment


National second class key protected species of China (Fig.1)


Vulnerable (VU) species on IUCN Red List (Fig. 2)


Species on CITES appendix 



Figure 1. Asian small-clawed otter as one of national second class key protected species of China (origin: forestry.gov.cn)


2. 亚洲小爪水獭IUCN红色名录保护级别(来源IUCN

Figure 2. The assessment level of Asian small-clawed otter on IUCN red list (origin: IUCN)


3. 形态特征Physical Description





3. 亚洲小爪水獭实体图(作者James Dowling-Healey;来源Animal Diversity Web

Figure 3. Asian small-clawed otter (contributor: James Dowling-Healey; origin: Animal Diversity Web)



4. 亚洲小爪水獭头部示意图(作者Tim Ellis,来源IUCN

Figure 4. The head of Asian small-clawed otter (contributor: Tim Ellis; origin: IUCN)



5. 亚洲小爪水獭使用前爪取食示意图(作者David Blank;来源Animal Diversity Web

Figure 5. An Asian small-clawed otter using its forepaws to eat (contributor: David Blank; origin: Animal Diversity Web)



头骨小、短且宽虽然牙齿大小与欧亚水獭Lutra lutra和江獭Lutrogale perspicillata的相似,但头骨明显更小小于9厘米)。小爪水獭的最后的两颗上牙更大,其形状非常适合压碎螃蟹和其他硬壳猎物的外骨骼。



6. 三种中国水獭对比图(来源《中国兽类野外手册3:亚洲小爪水獭;4:欧亚水獭;5:江獭

Figure 6. Comparing among the three otter species distributed in China (origin: A Guide to the Mammals of China); 3: Asian small-clawed otter4: Eurasian otter; 5: smooth-coated otter


The Asian small-clawed otter is the smallest otter species in the world and is stocky than other otters. Body length is 40-61 cm, tail is 29-35 cm long, and weigh is 2-4 kg.

Otters have a thick coat of fluff hairwith the density up to about 70,000 hairs per square centimeter, and a long layer of bristles that insulate air when they're in the water.

The Asian small-clawed otter is uniformly dark brown on the head, back, limbs and tail, and grayish white on the lower cheeks, throat and chest (Fig. 3).

They have long, dense tentacles on their faces. They have small, round ears, which are rounder than other otters, and they have relatively larger eyes (compared to the size of other otters' eyes relative to their head). Otters have valves in their ears and nostrils that automatically close underwater, preventing water from entering (Fig. 4).

The toes of the fore-paws are short, strong and flexible, with small, degenerated claws at the ends that resemble wooden spikes at the bulbous ends (Fig. 5, 6). Their front paws can be used to dig through dirt and lift rocks, as well as to hunt.

The caudal base is broad and thick, but the caudal end suddenly becomes sharp, and the dorsal and ventral sides are flattened.

The skull is small, short and wide. While the teeth are similar in size to those of Eurasian otters (Lutra Lutra) and smooth-coated otters (Lutrogale perspicillata), the skull is significantly smaller (less than 9cm). The last two upper teeth of the small-clawed otter are larger and are perfectly shaped to crush the exoskeletons of crabs and other hard-shelled prey.

When seen from a distance in the wild, it may be difficult to distinguish it from its close relative, Eurasian otter, and small-clawed otter is much smaller than Eurasian otter (Fig.6 ).


4. 地理分布Geographic Range




7. 小爪水獭世界范围地理分布(来源IUCN

Figure 7. Geographic range of Asian small-clawed otter around the world (origin: IUCN)





8. 亚洲小爪水獭中国分布(来源中国兽类野外手册

Figure 8. Geographic range of Asian small-clawed otter in China (origin: A Guide to the Mammals of China)

This species distributes in mainly tropical and subtropical areas of Asia, including South and Southeast Asia, and extending to the southern foothills of the Himalayas and south China.

Distribution countries: China, Nepal, Bhutan, Bangladesh, India, Laos, Myanmar, Cambodia, Vietnam, Thailand, Malaysia, Singapore, Philippines, Brunei, Indonesia (Fig. 7).

Distribution in China: the small-clawed otter was once widely distributed in many provinces and regions in south and southwest China, including Fujian, Guangdong, Guangxi, Guizhou, Yunnan, Sichuan, Xizang, Hainan and Taiwan (Fig. 8), but only a few locations in western Yunnan have been confirmed in recent years.


5. 栖息环境Habitat





Small-clawed otters are adapted to semi-aquatic life, living in a variety of wetland systems, including streams, ponds, paddy fields, marshes and mangroves;  They prefer slow-flowing or static, shallow and small water bodies.

 The distribution altitude can reach 2000 meters.

 They are sometimes sympatric with Eurasian otters and smooth-coated otters, but the small-clawed otter prefers small bodies of water. And their main food species are different. Smooth-coated otters mainly prey on large fish, Eurasian otter on small fish and frogs, and small-clawed otter on freshwater crabs.

 Small-clawed otters don't like completely naked and unprotected habitats.

6. 生活习性Ecology

6.1 食物Food Habits





Small-clawed otters are carnivores, feeding mainly on aquatic animals. Their forage a high diversity of food, including freshwater crabs, small fish, snails, shellfish, amphibians (frogs, etc.), insects, reptiles (lizards, snakes, etc.) and birds.

In many areas, their main food is freshwater crabs. But there may be some areas where the crab density is low and their diet may change. Small-clawed otters may have different food compositions in different regions, and as opportunistic predators, small-clawed otters will choose preys according to their availability.

Small-clawed otters hunt with their front paws.

They will put the shellfish under the sun and wait for the shells to open before eating them.

6.2 社群Sociality



Small-clawed otter are highly social animals. The group size is usually 4-12, and sometimes 12-15 individuals gather together to forage. These groups consist of a pair of dominant females and dominant males and their successive litters of offspring.

Their bird-like squeaks help them find each other in wild, but their social vocabulary goes far beyond that and they have developed a dozen or more different types of calls.

6.3 领域Home Range


Small-clawed otters use regular scent-marks to mark different territory.

6.4 节律Rhythm


They are active at sunrise and sunset.

7. 繁殖







Small-clawed otters are monogamy, which live in pairs.

Female estrus cycles range from 28 to 30 days and can reproduce at any time of the year. Some captive facilities find that older individuals become estrus every few months. Estrus lasts 1 to 13 days. Signs of estrus may include rubbing and increased marking.

In captivity, mating usually takes place in water, but sometimes also onshore.

Gestation lasts 60 days. Adult females can give birth to two cubs per year, with a litter size of two to seven and an average of four to five.

Usually both parents participate in raising the young. But, unlike Eurasian otters, they're not very good at that. After living with their parents for more than a year, the cubs join unrelated groups. Sexual maturity occurs at 2.5 years of age.

The lifespan of an individual in captivity is about 11 years.

8. 生态系统中作用Ecosystem Role




9. 水獭是捕食者(作者Lyn Wells

Figure 9. Otters as predators (Contributor: Lyn Wells )


The wetlands refer to areas of the sea and the inland with perennial shallow water or soil wet. It is well known that wetlands are one of the most valuable habitats of biodiversity and economic value, but they are still declining. In fact, it is estimated that since the industrialization era, the extent of the world's wetlands has been reduced by up to 87%. Human use of wetlands can have a serious impact on the diversity of life.

Otters are predators (Fig. 9) who use both land and aquatic environments , which can have an important impact on food nets, biodiversity and habitat.

Otters live in many different aquatic environments: coast, estuaries, rivers, lakes, canals, marshes, etc. They need good water quality and unpolluted natural land habitat.  These are essential for all species, including human, so they are excellent environmental indicator species.

9. 保护现状Conservation Status








栖息地流失 城市化进程湿地排水大坝建设河岸植被清除等

人为干扰 噪音增加划船活动和采砂增加。

路杀 许多水獭在试图回家的路上死于道路上。

与渔业的竞争 :水獭同渔业的竞争可能导致狩猎水獭,然后成为非法野生动植物贸易的来源。在某些国家地区,例如奥地利,目前已批准使用合法的水獭捕捉工具。

诱捕 水獭在许多国家地区都受到法律保护,但在北美,有50,000只水獭被诱捕合法杀死。

非法贸易 毛皮和宠物。 



Figure 10. Multiple threats faced by otters

Small-clawed otters’ survival faces multiple threats, including capture as live pets, fur harvesting, and habitat destruction. In the face of many threats, the population number of small-clawed otter is declining.

In fact, it's not just the small-clawed otter. There are 13 species of otter in the world, and otters are found on all continents except Antarctica and Oceania. They're all on the Red List of threatened species. With the exception of North American otter populations, whose population number has held steady, all other otter species are in decline. Even so, however, population trends of North American otters are questionable, as thousands of individuals are legally killed by trapping each year.

In the past, otters face many problems with their survival, including hunting for fur and pollution. Take the Eurasian otter as an example:

It wasn't until the middle of the 20th century that people realized that otters were disappearing rapidly from Europe, and pollution was to blame. Various chemicals (organochlorine) are used in agriculture and they are making their way into the environment. These, along with PCBS and heavy metals, affect not only otters, but also birds at the top of the food chain. These chemicals even show up in human milk! As a result, people began to understand the importance of maintaining environmental quality and began to make efforts to do so.

As water quality improved in Europe, species including otters began to recover. Otters, however, do not recover quickly because they breed slowly and usually do not live long.

Nowadays, otters around the world still face many threats (Fig. 10) :

Pollution: microplastics, chemical leaks, agricultural and industrial waste, and garbage.

Habitat lossurbanization, wetland drainage, dam construction, riparian vegetation removal, etc

Human interference: noise increases, boating activity increases, and sand mining increases.

Load killmany otters die on the roads trying to get home.

Competition against fishing: Competition between otters and fishing can lead to otter hunting, which in turn becomes a source of illegal wildlife trade. In some countries or areas, such as Austria, the use of legal otter trapping tools is now approved.

Trappings: Otters are protected by law in many countries and regions, but 50,000 otters are legally killed by snares in North America.

Illegal trade: fur and pets.





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