Oriental Small-clawed Otter, Aonyx cinerea

The oriental small-clawed otter (Aonyx cinerea) is also known as the Asian small-clawed otter. The range of this otter includes Burma, Bangladesh, India, Taiwan, Laos, southern China, Indonesia, Thailand, Vietnam, the Philippines, and Malaysia. This otter was thought to be a single member in the genus Amblonyx, but it has been recently classified as Aonyx due to research on its mitochondrial DNA.

The oriental small-clawed otter prefers to live in freshwater wetlands and mangrove swamps within its range. Its lives in extended family groups of up to twelve otters, and resides in burrows within muddy banks. These otters prefer covered habitats, including irrigated rice fields, and choose not to live in open areas. They will spend much of their time on land, unlike other species of otters.

With an average length of up to 3.3 feet, the oriental small-clawed otter is the smallest otter in the world. They typically weigh between 2.2 and 11.9 pounds. This otter has a slender body, which allows for increased grooming. It can groom nearly all of its dark brown-grey fur. The underbelly is typically a light cream in color and this appears most commonly the face and neck. Each otter has two kinds of fur: on the top layer, there are coarse guard hairs and beneath that is a velvety undercoat.

The oriental small-clawed otter has a compacted head and a short, thick neck. The ears are equipped with a valve-like construction, which allows the otter to close its ears when it dives underwater. This otter’s nose pads are tawny-pink in color, and whiskers on the muzzle allow for increased sensitivity to movements of prey and vibrations in water. The tail on this otter makes up nearly one third of its body, and is used for swimming at quick speeds, steering when swimming leisurely, and balancing when standing upright.

As with other otters, the oriental small-clawed otter has squat legs, which they use for swimming, walking, grooming, and manipulating food. The feet are webbed up to the last joint in the toe, and this distinguishes them from all other species of otter. This feature, along with shortened claws the never extend past the paw-pad, allow the small-clawed oriental otter to have better dexterity when handling prey.

The diet of the oriental small-clawed otter consists mainly of invertebrates such has crabs and other crustaceans, amphibians, and mollusks. They will also feed on small fish and insects, but their teeth, particularly the front two, are used for breaking open hard shells of its more preferred prey. These otters will supplement their diets with frogs, snakes, and rodents when needed. Instead of using their mouth to catch prey, these otters will use their hands, and are skilled at catching prey or digging it up from muddy banks.

The oriental small-clawed otter can be found living in remote areas, secluded from human actions. They are diurnal, active in the daytime. Grooming is very important to maintaining the insulating quality of the fur, and they will groom many times throughout the day. They will roll on the ground using logs or vegetation to dry their fur. This otter is skilled at swimming, and will use its hind feet and tail when swimming quickly, and use all four feet when paddling or floating atop the water. The oriental small-clawed otter is capable of diving underwater for six to eight minutes. It can be seen playing and frolicking along muddy banks in its habitat, and when protected its homes may fight or scratch. These otters will sleep above ground, or in their dens. Defecating plays an important role in communication between otters, and when using this method, the otters will release small amounts of feces known as spraints. If a spraint contains an unfamiliar scent, then the otter knows that a strange individual is near.

The oriental small-clawed otter will use other forms of communication, including twelve types of vocalizations and scent markings. Scent, however, is the most important form of communication between otters. When marking their territory, these otters will scent their spraint using glands under the tail. Spraints can be found along trails, pool edges, boulders, and within tree trunks. Another form of communication, sign heaps, involves the otter creating a pile of sand, grass, mud, or gravel, allowing otters to know when others are near. Social interactions such as grooming, posturing, or hormonal changes are other forms of communication for this otter.

The oriental small-clawed otter will mate for life, and can have up to two litters a year containing up to six pups. These pups are born helpless, blind, and toothless and will spend their first few weeks sleeping and eating, hidden in the den. After a period of forty days, the pups can open their eyes and up to forty days after that, the pups will begin to eat solid food. Three months after this time, the pups will begin to swim. Pups will remain with their mother until another litter is born. The oriental small-clawed otter can live to be sixteen years old.

Considering the diet of the oriental small-clawed otter, mainly crabs, it is widely thought to aid in population control of agricultural pests. However, they have been known to destroy plants by uprooting them and are sometimes considered pests themselves because of this.

Threatened by habitat destruction, pollution, and hunting, the oriental small-clawed otter has been listed as “Vulnerable” on the IUCN Red List . Measures are being taken to preserve the otter population, although they are still decreasing despite their protected status and areas. SeaWorld breeds the small-clawed otters as part of their Association of Zoos and Aquariums’ Species Survival Plan. At Zoo Basel, there is one of the largest oriental small-clawed otter exhibits. Although it only houses two otters, it is made up of 21,528 square feet and includes over twelve tunnels, two rivers, and four ponds. The otters share their “sprawling” habitat with muntjacs and Indian rhinoceroses.

Image Caption: This is an otter found in the hill streams of the Western Ghats, Southern India. Credit: Clusteronefloyd/Wikipedia(CC BY-SA 3.0)