The mugger crocodile (Crocodylus palustris) is also known as broad-snouted crocodile, marsh crocodile, and mugger. It is a crocodilian endemic to freshwater habitats from the Indian subcontinent to southern Iran.
It is extinct in Myanmar and Bhutan and has been listed on the IUCN Red List as Vulnerable since 1982.
It is a medium-sized crocodile that inhabits rivers, lakes, artificial ponds, and marshes. Both adult and young mugger crocodiles dig burrows where they retreat when the temperature drops below 41 °F (5 °C) or exceed 100 °F (38 °C).
Female mugger crocodiles dig holes in the sand as the nesting sites. The female may lay approximately 50 eggs during the dry season.
The adult preys on reptiles, fish, mammals, and birds, while the young feed on insects. It is one of the crocodilians in India, apart from gharial (Gavialis gangeticus) and saltwater crocodile (C. porosus).
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Mugger crocodile hatchlings colourations are pale olive and black spots. Adults are grey to dark or brown. There are large scutes around the neck that are well separated from the back and also, the head is rough without any ridges.
Scutes usually form 4, rarely 6 longitudinal series and 16 – 17 transerve series. The limbs are known to possess keeled scales with serrated fringes located on the outer edges. The mugger crocodile outer toes are webbed.
The snout is fairly longer than broad with nineteen upper teeth on each side. The symphysis of the lower jaws is said to extend to the level of the 4th – 5th tooth.
The mugger crocodile is believed to be a medium-sized crocodilian but has the broadest snout among all extant crocodilians. It has webbed feet and a powerful tail. Its hearing, visual, and smelling senses are acute.
Adults female muggers are 6 ft 7 in – 8 ft 2 in (2 – 2.5 m) on average, and male muggers 9 ft 10 in – 11 ft 6 in (3 – 3.5 m). They rarely grow up to 16 ft 5 in (5 m). The largest known mugger crocodile measured 18 ft 6 in (5.63 m). One male mugger crocodile in Pakistan of about 9 ft 10 in (3 m) weighed 430 lb (195 kg).
Diet and hunting
The mugger crocodile preys on snakes, fish, birds, turtles, and mammals including squirrels, monkeys, otters, rodents, and dogs.
It scavenges on dead animals. During the dry season, mugger crocodiles walk many kilometres overland in search of prey and water.
Hatchlings feed on insects such as beetles, but also on shrimp and crabs. After a few months, the hatchling will feed on vertebrates.
Subadult and adult mugger crocodiles favour fish but also prey on small – medium-sized ungulates up to the size of chital (Axis axis). Adult mugger crocodiles also feed on tortoises and turtles.
Female mugger crocodiles reach sexual maturity at a body length of around 5.9 to 7.2 ft (1.8 to 2.2 m) at the age of about six and a half years, and males at around 8 ft 6 in (2.6 m) body length.
Between February – June, females dig 1.15 to 1.84 ft (35 to 56 cm) deep holes for nesting, which may be up to 3.3 – 6,561.7 ft (1 – 2,000 m) away from the waterside. They lay up to two clutches with 8 – 46 eggs each. Eggs weigh 4.5 oz (128 g) on average.
Males have been observed to assist females in protecting and digging nest sites. Hatchlings season is 2 months later, between April – June in South India, and Sri Lanka between August – September. Then the female excavates the young, by picking them up in their snout and takes them to the water. Both parents protect the young for more than a year.
Healthy hatchlings mature at a temperature range of 82 to 91 °F (28 to 33 °C). Only females develop at constant temperatures 82 to 88 °F (28 to 31 °C), and only males at 90.5 °F (32.5 °C).
The percentage of females in a clutch decreases at various constant temperatures between 90.7 – 91.4 °F (32.6 – 33 °C), and of males between 87.8 – 90.3 °F (31 – 32.4 °C). The temperature in natural nests is not always constant but varies between days and nights.
Hatchlings are 10 to 12 in (26 to 31 cm) long and weigh 2.6 oz (75 g) on average when one month old. They grow about 1.67 in (4.25 cm) per month and reach a body length of 35 to 67 in (90 to 170 cm) when two years old.
Habitat and distribution
The mugger crocodile occurs in Pakistan, southern Iran, India, Nepal, and Sri Lanka, but is assumed to be extinct in Bangladesh.
It inhabits rivers, freshwater lakes, and marshes. It prefers slow-moving, shallow water bodies. It is known to survive in irrigation canals and artificial reservoirs.
In Nepal’s Terai, it occurs in wetlands of Bardia National Parks, Shuklaphanta, Ghodaghodi Tal Koshi Tappu Wildlife Reserve and Chitwan National Parks.
In India, it occurs in:
- Rajasthan along the Chambal, in Ranthambore National Park, and Ken and Son Rivers
- Gujarat along the Vishwamitri River
- Uttarakhand’s Rajaji National Park, Lansdowne Forest Division, and Corbett Tiger Reserve
- Madhya Pradesh’s National Chambal Sanctuary
- Kishanpur Wildlife Sanctuaries and Uttar Pradesh’s Katarniaghat
- Mahanadi and Sabari Rivers and Odisha’s Simlipal National Park
- Telangana’s Manjira Wildlife Sanctuary
- Warna Rivers and Maharashtra’s Kadavi
- Goa’s Salaulim Reservoir, in small lakes and Zuari River
- Neyyar Wildlife Sanctuary and Kerala’s Parambikulam Reservoir
- Amaravathi Reservoir and Tamil Nadu’s Moyar River
In Sri Lanka, it occurs in several national parks such as Yala, Wilpattu, and Bundala National Parks.