Mugger crocodile

The mugger crocodile (Crocodylus palustris) is a medium-sized broad-snouted crocodile, also known as mugger and marsh crocodile. It is native to freshwater habitats from south-eastern Iran to the Indian subcontinent, where it inhabits marshes, lakes, rivers and artificial ponds. It rarely reaches a body length of and is a powerful swimmer, but also walks on land in search of suitable waterbodies during the hot season. Both young and adult mugger crocodiles dig burrows to which they retreat when the ambient temperature drops below or exceeds . Females dig holes in the sand as nesting sites and lay up to 46 eggs during the dry season. The sex of hatchlings depends on temperature during incubation. Both parents protect the young for up to one year. They feed on insects, and adults prey on fish, reptiles, birds and mammals.

The mugger crocodile evolved at least and has been a symbol for the fructifying and destructive powers of the rivers since the Vedic period. It was first scientifically described in 1831 and is protected by law in Iran, India and Sri Lanka. Since 1982, it has been listed as Vulnerable on the IUCN Red List. Outside protected areas, it is threatened by conversion of natural habitats, gets entangled in fishing nets and is killed in human–wildlife conflict situations and in traffic accidents.

Taxonomy and evolution

Crocodilus palustris was the scientific name proposed by René Lesson in 1831 who described the type specimen from the Gangetic plains. In subsequent years, several naturalists and curators of natural history museums described zoological specimens and proposed different names, including:

C. bombifrons by John Edward Gray in 1844 for a specimen sent by the Museum of the Royal Asiatic Society of Bengal to the British Museum of Natural History.
C. trigonops also by Gray in 1844 for a young mugger specimen from India.

A paleogenomics analysis indicated that Crocodylus likely originated in Africa and radiated towards Southeast Asia and the Americas, diverging from its closest recent relative, the extinct Voay of Madagascar, around near the Oligocene/Miocene boundary.

Within Crocodylus, the mugger crocodile's closest living relatives are the Siamese crocodile and the saltwater crocodile. In Andhra Pradesh's Prakasam district, a long fossilized skull of a mugger crocodile was found in a volcanic ash bed that probably dates to the late Pleistocene. Crocodylus palaeindicus from late Pliocene sediments in the Sivalik Hills is thought to be an ancestor of the mugger crocodile. Fossil remains of C. palaeindicus were also excavated in the vicinity of Bagan in central Myanmar.

Below cladogram is from a tip dating study, for which morphological, molecular DNA sequencing and stratigraphic fossil age data were simultaneously used to establish the inter-relationships within Crocodylidae.

The mugger crocodile is considered a medium-sized crocodilian, but has the broadest snout among living crocodiles. It has a powerful tail and webbed feet. Its visual, hearing and smelling senses are acute. Adult female muggers are on average; males usually measure , but rarely reach a length of . The two largest known muggers measured and were killed in Sri Lanka.

One individual weighing had a bite force of . Large males may reach a weight of .

The largest zoological specimen in the British Museum of Natural History measures .

Distribution and habitat

The mugger crocodile occurs in southern Iran, Pakistan, Nepal, India and Sri Lanka up to an elevation of .

In Pakistan, a small population lives in 21 ponds around Dasht River; in the winter of 2007–08, 99 individuals were counted. By 2017, the population had declined to 25 individuals. In Sindh Province, small mugger populations occur in wetlands of Deh Akro-2 and Nara Desert Wildlife Sanctuary, near Chotiari Dam, in the Nara Canal and around Haleji lake.

In Nepal's Terai, it occurs in the wetlands of Shuklaphanta and Bardia National Parks, Ghodaghodi Tal, Chitwan National Park and Koshi Tappu Wildlife Reserve.

In India, it occurs in:

Rajasthan along the Chambal, Ken and Son Rivers, and in Ranthambore National Park
Gujarat along the Vishwamitri River and several reservoirs and lakes in Kutch
Madhya Pradesh's National Chambal Sanctuary
Uttarakhand's Rajaji National Park, Corbett Tiger Reserve and Lansdowne Forest Division
Uttar Pradesh's Katarniaghat and Kishanpur Wildlife Sanctuaries
Odisha's Simlipal National Park and along Mahanadi and Sabari Rivers In 2019, 82 individuals were recorded in the river systems of Simlipal National Park.
Telangana's Manjira Wildlife Sanctuary and Savitri River in Raigad District.
Goa's Salaulim Reservoir, Zuari River and in small lakes
Tamil Nadu's Amaravathi Reservoir, Moyar and Kaveri rivers.

In Sri Lanka, it occurs in Wilpattu, Yala and Bundala National Parks. Between 1991 and 1996, it was recorded in another 102 localities.

In Bangladesh, it was historically present in the northern parts of the Sundarbans, where four to five captive individuals survived in an artificial pond by the 1980s. It is possibly locally extinct in the country.

In Bhutan, it became extinct in the late 1960s, but a few captive-bred individuals were released in the Manas River in the late 1990s. Burrows are between deep, with entrances above the water level and a chamber at the end that is big enough to allow the mugger to turn around. Hatchlings feed mainly on insects such as beetles, but also on crabs and shrimp and on vertebrates later on. It seizes and drags potential prey approaching watersides into the water, when the opportunity arises. Adult muggers were observed feeding on a flapshell turtle and a tortoise. Subadult and adult muggers favour fish, but also prey on small to medium-sized ungulates up to the size of chital (Axis axis).

At the Chambal River, muggers have attacked water buffaloes, cattle and goats.

In Bardia National Park, a mugger was observed caching a chital kill beneath the roots of a tree and returning to its basking site; a part of the deer was still wedged among the roots on the next day.

Muggers have also been observed preying and feeding on pythons.

Tool use

Mugger crocodiles have been documented using lures to hunt birds. This means they are among the first reptiles recorded to use tools. By balancing sticks and branches on their heads, they lure birds that are looking for nesting material. This strategy is particularly effective during the nesting season.

Reproduction

Female muggers obtain sexual maturity at a body length of around at the age of about 6.5 years, and males at around body length. The reproduction cycle starts earliest in November at the onset of the cold season with courtship and mating. Between February and June, females dig deep holes for nesting between away from the waterside. They lay up to two clutches with 8 –46 eggs each. Eggs weigh on average. Laying of one clutch usually takes less than half an hour. Thereafter, females scrape sand over the nest to close it. Males have been observed to assist females in digging and protecting nest sites. Hatching season is two months later, between April and June in south India, and in Sri Lanka between August and September. Then females excavate the young, pick them up in their snouts and take them to the water. Both females and males protect the young for up to one year. Hatchlings are long and weigh on average when one month old. They grow about per month and reach a body length of when two years old. |image2=A_male_tiger_with_huge_crocodile_at_Rajbaugh,_Ranthambhore.jpg |caption2=A mugger crocodile and a tiger in Ranthambore National Park |image3=Marsh_Mugger_and_Gharial_(42701836700).jpg |caption3=Mugger crocodile and gharial

The distribution of the mugger crocodile overlaps with that of the saltwater crocodile in a few coastal areas, but it barely enters brackish water and prefers shallow waterways. It is an apex predator in freshwater ecosystems. It is sympatric with the gharial (Gavialis gangeticus) in the Rapti and Narayani Rivers, in the eastern Mahanadi, and in tributaries of the Ganges and Yamuna rivers.

The Bengal tiger (Panthera tigris tigris) occasionally fights mugger crocodiles off prey and rarely preys on adult mugger crocodiles in Ranthambore National Park. The Asiatic lion (Panthera leo leo) sometimes preys on crocodiles on the banks of the Kamleshwar Dam in Gir National Park during dry, hot months.

Threats

The mugger crocodile is threatened by habitat destruction because of conversion of natural habitats for agricultural and industrial use. As humans encroach into its habitat, the incidents of conflict increase. Muggers are entangled in fishing equipment and drown, and are killed in areas where fishermen perceive them as competition.

Between 2005 and 2018, 38 mugger crocodiles were victims of traffic accidents on roads and railway tracks in Gujarat; 29 were found dead, four died during treatment, and five were returned to the wild after medical care.

Conservation

The mugger crocodile is listed in CITES Appendix I, hence international commercial trade is prohibited. It has been listed as Vulnerable on the IUCN Red List since 1982. By 2013, less than 8,700 mature individuals were estimated to live in the wild and no population unit to comprise more than 1,000 individuals.

In Iran, the mugger crocodile is listed as endangered and has been legally protected since 2013; capturing and killing a crocodile is punished with a fine of 100 million Iranian rials.

Since large muggers occasionally take livestock, this leads to conflict with local people living close to mugger habitat. In Maharashtra, local people are compensated for loss of close relatives and livestock. Local people in Baluchestan respect the mugger crocodile as a water living creature and do not harm it. If an individual kills livestock, the owner is compensated for the loss. The mugger crocodile is translocated in severe conflict cases. The Hindi word for crocodile is (). In English language, both names mugger and magar were used around the turn of the 20th century. The names 'marsh crocodile' and 'broad-snouted crocodile' have been used since the late 1930s.

The crocodile is acknowledged as the prototype of the makara and symbolises both the fructifying and the destructive powers of the rivers. It is the animal vehicle of the Vedic deity Varuna and of several nature spirits called yakshas. In Hindu mythology, it represents virility as a vehicle of Ganga and as an emblem of Kamadeva. A stone carving of a mugger crocodile was part of a beam of a gateway to the Bharhut Stupa built around 100 BC.

The traditional biography of the Indian saint Adi Shankara includes an incident where he is grabbed by a crocodile in the Kaladi river, which releases him only after his mother reluctantly let him choose the ascetic path of a Sannyasa. The Muslim saint Pir Mangho is said to have taken care of crocodiles and created a stream to trickle out of a rock near Karachi in the 13th century. This place was later walled around, and about 40 mugger crocodiles were kept in the reservoir called Magar Talao in the 1870s; they were fed by both Hindu and Muslim pilgrims. Mugger crocodiles have also been kept in tanks near Hindu temples built in the vicinity of rivers; these crocodiles are considered sacred. In the early 20th century, young married women fed the crocodiles in Khan Jahan Ali's Tank in Jessore in the hope of being blessed with children.

Vasava, Gamit and Chodhri tribes in Gujarat worship the crocodile god Mogra Dev asking for children, good crops and milk yield of their cows. They carve wooden statues symbolising Mogra Dev and mount them on poles. Their offerings during the installation ceremony include rice, milk, wine, heart and liver of a chicken, and a mixture of vermillion, oil and coconut fibres. Fatal attacks of mugger crocodiles on humans were documented in Gujarat and Maharashtra, but they rarely consumed the victims who died of drowning.

A fable from the Jataka tales of Buddhist traditions features a clever monkey outwitting a crocodile. Three folktales feature crocodiles and jackals. A mugger crocodile is one of the characters in The Undertakers, a chapter of The Second Jungle Book. The children's book Adventures of a Nepali Frog features the character Mugger, the crocodile who lives by the Rapti River in Chitwan National Park.

Etymology

The Sanskrit word makara is thought to derive from Proto-Dravidian *nek-V-ḷ- meaning "crocodile", with cognates in Kannada , ("alligator"), Tulu ("alligator"), and Telugu ("a marine animal which entangles swimmers"). This may have been derived from the root *neka- ("to rise, fly, jump, leap"), referring to the crocodile's jumping behavior when catching prey.

Alternatively, the word is traced to Proto-Dravidian *mokaray- ("crocodile"), a verbal noun from *mok- / *moṅku- meaning "to eat greedily, devour" (DEDR 5127 + 4897). This etymology explains widespread cognates including Bengali , Hindi , Tamil and Telugu . The phonological change from *mokara to makara reflects the absence of the short -o- vowel in early Indo-Aryan languages.

The Dravidian origin reflects early language contact, as Aryan speakers migrating from the Eurasian Steppe would not have had inherited words for crocodiles, adopting local terms upon reaching South Asia.