Table 5.

Habitat suitability in India.

Habitat	Legal Status	Elevation	Surface Water Availability	Water Quality	Nesting and Basking Site Availability	Interactions with Humans	Notes	Suitability
Kaveri River (Tamil Nadu, Karnataka, Kerala).	Part of the Kaweri flows in the boundaries of Cauvery Wildlife Sanctuary and Ranganathittu Bird Sanctuary.	41.88% of the basin lies below 400 masl.	Perennial river, multiple water bodies are located in the basin: over 42,000 lakes, ponds and reservoirs.	200 km stretch of river non-complying to the Water Quality Criteria [138].	The basin faces a serious issue of river bank erosion, with high slopes along most of its run.	There were 20 reported attacks on humans by muggers from 2009 to 2019 in Kaweri’s delta, seven of those being fatal [139].	There are 96 dams of varied size along the Kaweri. Parts of the river are located in regions with high human density; the human population growth was estimated at 17.25% in the region. There are a number of industries in the basin, including the textile industry, cement factories and metal plants.	Moderate.
Kabini River (Kerala, Karnataka).	Not under legal protection.	N/A	Perennial river.	5 km polluted stretch of the river [140]. Heavy metal pollution in sediment samples, namely manganese, copper and zinc [141].	Siltation is observed around the river banks [142].	The river is mainly utilized as water source for crops and livestock, with intense fishing in Kittur village only [142].	There is one large dam—Kabini dam—creating a vast reservoir. Currently, the Kabini river is a candidate for developing an Inland Water Transport route, which would require human interference into river banks [142]. The main pollution sources are sewage discharge and municipal solid waste in Nanjanagud [143].	Moderate.
Kollidam Canal (Tamil Nadu).	Not under legal protection.	N/A	Perennial canal, high risk of flooding due to sediment deposition from sand mining operations	Heavy metal contamination (copper and cadmium) in estuarine sediments and five species of freshwater fish [144].	Severe river bank erosion due to both legal and illegal sand mining [145].	There were 20 reported attacks on humans by muggers from 2009 to 2019 in Kaweri’s delta, seven of those being fatal [139].		Bad.
Bhavani River (Kerala, Tamil Nadu).	Not under legal protection.	200–3000 masl.	Perennial river, threatened by decreasing groundwater levels [146].	Heavy metal contamination, fluoride concentration exceeding permissible limit on a 60 km stretch of Bhavani [146].	N/A	N/A	Contamination results from considerable industrialization of the region, with 400 units of paper, dyeing, sugar and bleaching industries, that both use Bhavani’s water and expel waste into the river [147,148]. Tamil Nadu Pollution Control Board recognizes discharge of untreated domestic sewage as the main pollution source [149]. There are two dams on Bhavani, out of which Bhavani Sagar is known to house crocodiles. It is one of the largest earthen dams in the world and creates the second largest reservoir in Tamil Nadu, with capacity of 928,000,000 m3 [148,150].	Moderate.
Amaravathi River (Tamil Nadu).	Not under legal protection.	40–500 masl in the plains [151].	Perennial river.	Heavily polluted; Ahamed and Loganathan detected lead, cadmium and nickel that exceeded permitted levels for drinking water, and categorized gathered water samples as semi-critical in water quality [152].	N/A	N/A	Pollution is the major issue, due to textile and bleaching industry units located along the river [151,152]. Amaravathi Dam is believed to house one of the largest populations of muggers in India [18].	Moderate.
Moyar River (Karnataka, Tamil Nadu).	Partially flows through Mudumalai Tiger reserve, Sathyamangalam Tiger Reserve and Nilgiri North and South Divisions.	250–2054.	Perennial river.	Stretches of river are under considerable eutrophication.	N/A	Agricultural runoff, hydroelectric projects, unrestricted fishing activities (including occasional use of dynamite), pesticides and spilling of motor oil [128].		Moderate.
Bhadra River (Karnataka)	Falls under Bhadra Wildlife Sanctuary and Bhadra Tiger Reserve.	N/A	Perennial river.	There is an identified 10 km stretch of polluted water starting at Holehunnur and ending at Bhadravathi [140,153].	N/A	N/A		Data deficient.
Kali River (Karnataka).	Not under legal protection.	N/A	Perennial river.	Identified as polluted on a 10 km stretch of Dandeli, due to sewage discharge [154].	N/A	The river is utilized for tourism and recreational purposes and fishing. There are five reports of mugger attacks on humans in Kali’s vicinity in the last decade. Rising frequency of attacks on humans is likely caused by construction on the river in Dandeli.		Moderate.
Neyyar Wildlife Sanctuary (Kerala).	Protected Area.	100–1868 masl.	Reservoir.	Moderate [155].	Erosion of reservoir banks [156].	36 muggers were reintroduced into Neyyar reservoir in 1983, which resulted in considerable fueling of human–crocodile conflict, due to 30 reported attacks from 1983 to 2001 [126,157]. Locals also reported frequent attacks on livestock [126]. Local attitude towards crocodiles was reported as hostile in 2001 [126].	Vijayasoorya et al. reported degradation of forest cover in the sanctuary, which, according to landscape analyses, declined by 10% between 2011 and 2015 [158].	Moderate.
Parambikulam Tiger Reserve (Kerala).	Protected Area.	300–1438 masl.	Apart from Parambikulam, there are two other man-made reservoirs and two rivers flowing through the reserve.	N/A	N/A	N/A		Data deficient.
Vishwamitri River.	Not under legal protection.	N/A	Seasonal river, susceptible to flooding.	The river is heavily polluted due to sewer and industrial waste disposal and solid waste dump sites [159].	Suitable nesting sites available [160].	Numerous attacks on livestock and domestic animals suggest dependency of crocodiles on livestock as food source [131]. They are also observed scavenging on dumping sites and on carcasses, possibly illegally dumped into the river by hospitals [131]. From the period of 2014–2015 alone, 24 attacks on humans were reported, 12 being fatal [161].	The river is surrounded by urban, rural and industrial landscape, the historic river being converted into a sewer [159].	Moderate.
Narmada River (Madhya Pradesh, Gujarat).	Not under legal protection.	N/A	Perennial river.	160 km stretch of polluted river in the boundaries of Madhya Pradesh [100].	N/A	Indian media report five attacks on humans in last decade.	There are 21 major dams on the river [162].	Moderate.
Kaliyasot Dam (Madhya Pradesh).	Not under legal protection.	N/A	Reservoir.	Moderate, high turbidity and alkalinity, high nitrate and sulphate levels [163,164].	Suitable nesting sites.	Human disturbance and frequent encroachment.	Kaliyasot dam is located within Bhopal, a city with a population of two million. According to Silawat and Chauhan, the reservoir is under high environmental stress due to human encroachment, siltation, high macrophytic growth and sewage discharge [163].	Moderate/bad.
Godawari River (Maharashtra, Telangana, Andhra Pradesh, Chhattisagarh, Odisha).	Not under legal protection.	N/A	Perennial river.	N/A	N/A	N/A	The river is under environmental stress due to rapid urbanization, building of dams, destruction of riparian vegetation, unregulated construction along river banks a sewer discharge [165].	Data deficient.
Krishna River (Karnataka, Maharashtra, Andhra Pradesh).	Not under legal protection.	300–600 masl on the plateau [166].	Perennial river.	Central Pollution Control Board deemed that more than half of the river (750 km) should be considered polluted [140].	River banks susceptible to land sliding [167].	Atigre reports 16 attacks on humans and 62 attacks on cattle from 2003 to 2017 in Sangli district alone [168].	As of 2014, total of 660 dams were built on the Krishna [166]. In 2014, there were 11 894 industries in the basin, including sugar factories and sand mining operations [169]. MITRA recognizes the major sources of pollution to be disposal of untreated sewage, industrial effluent, agricultural runoff, religious waste, disposal of municipal solid waste, biomedical waste, hazardous waste and sand mining [169].	Moderate/bad.
Silimpal Tiger Reserve (Odisha).		500–600 masl.	Numerous perennial streams forming three main river systems [170].	N/A	N/A	Native tribes live in the vicinity of the reserve, with 65 villages falling into its boundaries, highly dependent on resources provided by the forests [171,172]. Poaching has become a big problem, especially during Akhand Shikar, a ritual mass hunting event. Losses in livestock to predators are an issue in the area.		Moderate.
Chambal River (Madhya Pradesh, Rajasthan, Uttar Pradesh).	Partially flowing through National Chambal Sanctuary.	111–843 masl.	Perennial river.	Good [173,174,175].	Suitable nesting sites.	Overfishing, drownings of crocodilians in fishing nets and illegal sand mining. Limited human–crocodile conflict in the area, mostly due to depredation of livestock.		Good.
Banas River (Rajasthan).	Not under legal protection.	176–1291 masl.	Seasonal river.	There is a 60 km long patch of the river polluted with chloride, nitrate and fluoride [176].	N/A	N/A	The Banas River has dried out since the Bisalpur Dam was completed in 1999, with restricted flow outside of monsoon season [134]. A proportion of 90% of Rajasthan was experiencing water stress as of 2014. There are occasional reports of gharial sightings in Banas [134].	Moderate.
Dudhwa Tiger Reserve (Uttar Pradesh).	Protected Area.	110–185 masl.	Three major rivers susceptible to flooding, seasonal streams.	Suheli and Mohana rivers are moderately polluted with sewer discharge, detergents and fertilizers [177,178].	After a channel shift due to a flood in 2010, sandy open banks of the river became covered in woody vegetation, limiting nesting spot availability for both muggers and gharials [179]. To remedy this transition, in 2020, a project meant to build additional sand banks was carried out [179]. Muggers and gharials alike swiftly adopted these sand banks, although the authors of the project warn that this solution is only temporary [179].	The three major Protected Areas forming Dudhwa Tiger Reserve are separated by privately owned land and 125 villages within a 5 km boundary (as of 2001), further causing encroachment into the forests and difficulties in maintaining the reserve’s role as an ecological corridor [180].		Moderate.
Gir National Park (Uttar Pradesh).	Protected Area.	N/A	Seven major perennial rivers, reservoirs, smaller rivers and streams and 388 artificial water points [181].	N/A	N/A	There is conflict between the park and local communities, as Maldharis settled in Gir forest caused major damage to the park by overgrazing livestock. Eventually, they were relocated outside of the Protected Area in 1972, but encroachment and overgrazing remain issues [181].	Mugger crocodiles inhabit major reservoirs in Gir forest and several rivers [181].	Data deficient.

N/A—data necessary for assessment not available.