Saltwater Crocodiles on Rise in Sundarbans

Context: As per the latest survey, the estimated population of saltwater crocodiles, one of the largest reptiles in the world, has increased in the Sundarban Biosphere Reserve (SBR).

Relevance of the Topic:Prelims: Key facts about crocodile species in India; Sunderbans. 

About Sundarbans

• The Sundarbans is a cluster of low-lying islands in the Bay of Bengal. Located in the delta of Rivers Ganges and Brahmaputra in India & Bangladesh.  
• Sunderban is the largest delta and mangrove forest in the world. It is the only mangrove forest in the world where tigers are found. 
• Area: covering ~10,000 sq km of which around 40% lies in India (rest in Bangladesh).
• Indian Sunderban is bounded on the west by river Muriganga and on the east by rivers Harinbhahga and Raimangal. Other major rivers flowing through this eco-system are Saptamukhi, Thakuran, Matla and Gosaba. 
• Protection status: 
  • Listed as UNESCO World Heritage Site
  • UNESCO Biosphere Reserve
  • Ramsar Site (2019)
  • Important Bird Area (IBA) under BirdLife International 
• Part of Sundarbans Tiger Reserve has been declared a critical tiger habitat under national law, and Tiger Conservation Landscape of global importance.  
• Fauna: Critically endangered northern river terrapin (Batagurbaska); endangered Irrawaddy dolphin; Other species include- Gangetic dolphins, Fishing cat, Olive Ridley Turtle, Tiger, Saltwater crocodile. 
• Flora: Dominated by Sundari tree (from which Sundarbans gets its name); Mangroves. 

Crocodiles in India

• India is home to three crocodile species- Gharial, Mugger, and Saltwater Crocodiles. 
• Crocodiles are cold-blooded animals usually spotted on banks of the aquatic systems.
• Crocodiles are apex predators and play a critical role in the ecosystem by maintaining biodiversity and ecological balance: they control the population of other aquatic animals. 
• Conservation:
  • All three crocodile species are placed under Schedule I of the Wildlife Protection Act 1972. 
  • India launched Crocodile Conservation Project in Odisha's Bhitarkanika National Park in 1975 with aid from United Nations Development Programme.

1. Saltwater Crocodile:

• Largest of all crocodile species and the largest reptile in the world. Recognised as a man eater.
• It is a hypercarnivorous apex predator that keeps flowing water ecosystems clean by feeding on the carcasses and wild remains in the water.
• Also known as estuarine crocodiles. It is distributed across the swamplands, rivers, mangroves of Odisha (Bhitarkanika National Park) and West Bengal (Sundarbans) and the coastal areas of the Andaman and Nicobar Islands.
• IUCN status: Least concern
• Concern: Increasing salinity may reduce the suitability of their habitat and may threaten their conservation, particularly in the Sundarbans which is vulnerable to climate change.
• Conservation Effort: Bhagabatpur Crocodile Project (conservation and breeding facility in West Bengal). 

2. Mugger: 

• They have a broad-snouted nose. They are also known as Marsh crocodiles. They are found in freshwaters like rivers and also in estuaries and marshy areas. 
• Mugger has a diverse and broad diet. They are known to dig burrows or holes for nesting purposes.
• Muggers have stronger legs which allow them to bask mainly on river banks choosing steeper slopes and elevated platforms.
• Their tough keratin scales are known to be sensitive to even the slightest motion in the water and this helps them detect prey easily. 
• IUCN status: Vulnerable

3. Gharials:

• They are endemic to the Indian subcontinent. 
• They are shy-natured and the most aquatic of all the species. 
• They are the longest living crocodile species, native to northern India and are distinguished by their long, narrow snouts. The gharials are predominantly a fish-eater.
• Gharials prefer to bask on mid-river sand islands on gentle slopes as they have weaker legs and can only crawl. 
• Chambal River (tributary of river Yamuna) holds the largest population of Gharials in the wild.
• IUCN status: Critically Endangered