The gharial, Gavialis gangeticus, is a crocodilian species facing an extreme conservation crisis. Recognized by its uniquely elongated snout, this freshwater reptile is the only surviving member of the family Gavialidae. The species is listed as Critically Endangered on the IUCN Red List of Threatened Species, reflecting a catastrophic population decline of over 96% since the 1930s. This severe decline highlights the urgent need for focused conservation efforts to prevent its extinction.
Unique Anatomy and Biology
The gharial possesses a morphology adapted to its specialized diet of fish, setting it apart from true crocodiles and alligators. Its most noticeable feature is the extremely thin, long snout, known as a rostrum, which is filled with approximately 110 razor-sharp, interlocking teeth. This slender jaw offers minimal resistance when swiftly sweeping underwater, allowing the gharial to snap up slippery fish with great efficiency.
Upon reaching sexual maturity, the male gharial develops a bulbous, cartilaginous growth at the tip of its snout called a ‘ghara,’ named after the Indian earthenware pot it resembles. This structure is a form of sexual dimorphism, functioning as a vocal resonator that amplifies a buzzing sound during courtship displays. The gharial is the most aquatic of all crocodilians, with weak leg muscles that limit its movement on land, except to bask or nest on sandy banks.
Historical and Current Range
Historically, the gharial was widely distributed across the major river systems of the Indian subcontinent, from the Indus River in Pakistan eastward across the Ganges and Brahmaputra river basins, and into the Irrawaddy River in Myanmar. This range once spanned over 20,000 linear kilometers of river habitat, and the species was common across these vast stretches of water.
This historical distribution has since contracted drastically to only about 2% of its former extent. Today, the wild population is confined to a handful of locations in India and Nepal. The most important remaining stronghold is the National Chambal Sanctuary, which protects a stretch of the Chambal River. Smaller, isolated populations persist in other Ganges tributaries, such as the Girwa and the Gandak rivers in India, and the Rapti-Narayani River in Nepal.
The Global Population Count
Global population estimates for the gharial are challenging to obtain, as the species is scattered across multiple fragmented populations. The most recent accepted global population estimate for mature, breeding adults is conservatively placed at approximately 650 individuals, ranging from 300 to 900. The total population, including all age classes, is currently estimated to be around 1,200 to 1,500 individuals globally.
The largest concentration of gharials is found within India’s National Chambal Sanctuary. This sanctuary is home to roughly 77% of the global mature population, with an estimated 500 mature adults and a total population of over 1,250 individuals. Counting gharials accurately presents a challenge due to their movement patterns, the difficulty of surveying remote river stretches, and high mortality rates among juveniles and sub-adults.
Principal Threats to Survival
The decline in gharial numbers is primarily driven by human activities that degrade their riverine habitat. The construction of dams and barrages has fragmented river systems, disrupting natural water flow and isolating populations with physical barriers the gharials’ weak limbs cannot easily traverse. Infrastructure development also leads to water abstraction for irrigation, transforming vast, free-flowing rivers into unsuitable, low-water habitats.
Sand and boulder mining pose a severe threat by destroying the steep, sandy riverbanks that gharials rely on for basking and nesting during the dry season. The loss of these stable nesting sites reduces successful reproduction and exposes eggs to increased risks from predators and erosion. Drowning after entanglement in fishing nets, particularly gill nets, also kills gharials of all sizes. Furthermore, pollution from agricultural runoff and industrial waste contaminates the water, impacting the gharial’s prey base and overall river health.
Strategies for Recovery
Conservation efforts focus on rebuilding wild populations and protecting remaining habitats. A primary strategy is captive breeding, often called “head-starting,” where eggs are collected from the wild, incubated in controlled environments, and hatchlings are reared to a larger size before being released into protected rivers. Facilities like the Kukrail Rehabilitation Centre in India have played a significant role in releasing thousands of captive-reared gharials into rivers like the Ganges.
Conservationists are also working to expand and reinforce protected areas, such as the National Chambal Sanctuary. Community engagement and awareness campaigns are implemented to reduce accidental mortality by encouraging local fishers and farmers to adopt practices that minimize conflict. These initiatives, which include helping communities identify and protect nesting sites, have led to the re-establishment of breeding in areas like the Gandak River.