Nilssonia nigricans (Black Softshell Turtle)

Nilssonia nigricans, commonly known as the Black Softshell Turtle, is a freshwater species native to South Asia. Once considered extinct in the wild, it survives mainly due to conservation efforts in temple ponds and protected areas. This species is known for its distinct dark-colored carapace and unique softshell structure.

Scientific Classification

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Family: Trionychidae
Genus: Nilssonia
Species: Nilssonia nigricans

Common Names

Black Softshell Turtle
Bostami Turtle

Identification

Description

The Black Softshell Turtle has a leathery, dark-colored carapace, often appearing black or dark brown. Its body is flattened with an elongated snout and a soft, flexible shell. The head and limbs are also dark, sometimes showing yellowish or orange markings.

Sexual Dimorphism

Females tend to grow larger than males, reaching up to 35 inches in shell length, while males remain smaller. Males also have longer tails compared to females.

Native Origin and Distribution

Geographical Range

Historically found in the Brahmaputra River basin of India and Bangladesh, the species now survives mainly in temple ponds, particularly in the Haigriv-Madhav temple pond in Assam.

Preferred Habitat

The species prefers slow-moving or still freshwater bodies like ponds, rivers, and wetlands with sandy or muddy bottoms. It thrives in warm, tropical climates with ample basking spots and vegetation.

Behavior

Feeding Habits

Black Softshell Turtles are carnivorous, feeding on fish, amphibians, insects, and carrion. They use their long snouts to detect prey in murky waters and have a powerful bite to capture food.

Predators

Juveniles face threats from birds, large fish, and other aquatic predators, while adults have fewer natural predators due to their size and agility in water. However, human activities pose a significant risk.

Reproduction

Breeding Season

The breeding season occurs during the monsoon months, typically between June and September, when water levels rise.

Reproductive Method

Females lay eggs in sandy riverbanks or isolated areas near water. Clutch sizes vary, with females depositing multiple eggs in a single nesting season. Hatchlings emerge after an incubation period of around 60 to 80 days.

Conservation

Extinction Status

Listed as Critically Endangered by the IUCN, with only a few known wild populations.

Threats

Habitat destruction, pollution, river damming, and excessive hunting for consumption and trade have severely impacted their numbers. The belief that temple ponds offer protection has helped some survive, but genetic bottlenecking remains a concern.

Conservation Measures

Efforts include captive breeding programs, habitat restoration, and strict legal protections. Conservationists work with local temples to safeguard existing populations and reintroduce individuals into suitable wild habitats.

Economic Importance

The species has limited economic value but holds cultural and religious significance, particularly in Hindu and Buddhist traditions. Conservation-driven tourism around temple ponds also contributes to local economies.

Interesting Facts

Black Softshell Turtles were once declared extinct in the wild until small populations were rediscovered in temple ponds.
Unlike many turtles, they lack a hard shell, making them more agile but vulnerable to predators.
They have a snorkel-like nose that allows them to breathe while partially submerged.
Some individuals in captivity have lived for over 50 years.