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Black Softshell Turtle (Bostami Turtle)

The black softshell turtle is a species on the verge of extinction. Existing populations of this species are limited to an artificial pond in the Bayazid Bastami shrine at Chittagong, and possibly three other locations (Assam, Kaziranga, and Jia Bhoroli River – Brahmaputra).

Due to their extremely limited number, conservation efforts are ongoing to save them from extinction.

Black Softshell Turtle Facts and Information

The black softshells used to be endemic to the lower Brahmaputra River in India and Bangladesh, however, their population is now limited to Assam in India where they depend on humans. Here they are known as the Bostami turtles.

The Nilssonia nigricans, as they are scientifically called, are softshell turtles. Like other softshells, this turtle has a leathery shell and a snorkel-like nose. The carapace of this species can grow up to 90 cm, which is 35½ inches or 3 feet. As you can see, these turtles are quite large.

The Nilssonia nigricans belongs to the family Trionychidae (Softshells), and the genus Nilssonia. Softshells prefer to live in freshwaters but many will adapt to live in brackish waters.

Almost all the Nilssonia nigricans existing now live in a freshwater pond. The genus Nilssonia contains other freshwater softshells endemic to the lakes, ponds, streams, and rivers of Myanmar/Burma and South Asia.

The appearance of the black softshell is similar to that of the Indian peacock softshell turtle (N. hurum), and the Ganges softshell turtle (N. gangeticus).

In fact, until recently, the black softshell was thought to be an inbred of both turtles. You can identify the black softshell using the structure of its leathery shell and plastron (underbelly). The shell of this turtle is olive green while its plastron is white.

Juvenile turtles have yellowish to orange plastron with 4 dark spots. The head and limbs are darkly colored. The digits of this species are webbed with three large claws on each limb.

The Bostami Turtle has a lifespan of up to 50 years.

Black Softshell Turtle Diet

Since there is hardly any N. nigricans in the wild, what they eat in the wild is unknown. The population found in Bayazid Bastami shrine is taken care of by humans.

However, we can assume this species eat the same food as that of other Nilssonia turtles. Nilssonia turtles are omnivores (although they are predominantly carnivorous) and eat both vegetation and animal foods such as carrion, frogs, fish, prawns, earthworms, and snails.

Black Softshell Turtle Habitat

Before their extinct in the wild status, the N. nigricans lived in abundance in rivers and wetlands around the lower Brahmaputra River.

In recent years, wild populations (with very few turtles) have been discovered in the Jia Bhoroli River – a tributary of the Brahmaputra River, and in the Kasopukhuri pond also in Assam. Also, a single wild black softshell turtle was discovered in the Wokha District in India.

At the moment, the only reliably known population live in an artificial pond at the Bayazid Bastami shrine as already mentioned. In 2014, a survey showed that the level of dissolved oxygen in the pond was below favorable levels.

These aquatic turtles spend most of their time in water. They do come out to bask as well as lay eggs.

Black Softshell Turtle Breeding

Little is known of the breeding habits of this rare turtle. It is known that they lay a clutch made up of 10 to 38 eggs. The eggs incubate for 92 to 108 days before hatching.

According to the staff of the Mazar Committee of the Bayazid Bastami shrine, 40 turtles hatched in 2014, two years earlier in 2010, 28 young N. nigricans hatched. Going further back, 170 turtles hatched in 2008 and 2009.

Black Softshell Turtle Predators

Due to their limited numbers, little is known of the predators of this species. The juveniles of this turtle may be preyed on by larger turtles.

Black Softshell Turtle Endangerment

In 2002, the N. nigricans was classified by the IUCN red list as extinct in the wild, since then a handful of these turtles have been discovered, however with such a limited population, these species are critically endangered.

As such, efforts are being made to save them. TSA (Turtle Survival Alliance) India is at the forefront of the conservation efforts. The TSA India has worked to improve conditions of habitats where the N. nigricans can be found. They have also hatched 44 turtles to date with the goal of eventually releasing them to supplement wild populations.

Bostami Turtles Being Fed (Video)


Although these turtles are on the brink of extinction, efforts are being made to save the species. Luckily, unlike other endeared turtles, there is no known trafficking of the species.

What do you think? Have you been to India and seen some? Let us know in the comments below and don’t forget to check out all the other turtle species!

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