The mugger crocodile (Crocodylus palustris) is a medium-sized broad-
snoutedcrocodile, also known as mugger and marsh crocodile. It is native to
freshwater habitats from southern
Iran to the
Indian subcontinent, where it inhabits
marshes,
lakes,
rivers and artificial
ponds. It rarely reaches a body length of 5 m (16 ft 5 in) 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 5 °C (41 °F) or exceeds 38 °C (100 °F). 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 4.19 million years ago 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.
Mugger crocodile hatchlings are pale olive with black spots. Adults are dark olive to grey or brown. The head is rough without any ridges and has large
scutes around the neck that is well separated from the back. Scutes usually form four, rarely six longitudinal series and 16 or 17 transverse series. The limbs have
keeled scales with
serrated fringes on outer edges, and outer toes are extensively webbed. The snout is slightly longer than broad with 19 upper teeth on each side. The
symphysis of the
lower jaw extends to the level of the fourth or fifth tooth. The
premaxillarysuture on the
palate is nearly straight or curved forwards, and the
nasal bones separate the premaxilla above.[18]
The mugger crocodile is considered a medium-sized crocodilian, but has the broadest
snout among
living crocodiles.[19] It has a powerful tail and webbed feet. Its
visual,
hearing and
smelling senses are acute. Adult female muggers are 2 to 2.5 m (6 ft 7 in to 8 ft 2 in) on average; males usually measure 3 to 3.5 m (9 ft 10 in to 11 ft 6 in), but rarely reach a length of 5 m (16 ft 5 in). The two largest known muggers measured 5.63 m (18 ft 6 in) and were killed in Sri Lanka.[20]
One individual weighing 207 kg (456 lb) had a
bite force of 7,295
N (1,640
lbf).[21] Large males may reach a weight of 450 kg (1,000 lb).[22]
The mugger crocodile occurs in southern Iran, Pakistan, Nepal, India and Sri Lanka up to an elevation of 420 m (1,380 ft).[2] It inhabits freshwater lakes, rivers and marshes, and prefers slow-moving, shallow water bodies. It also thrives in artificial
reservoirs and
irrigationcanals.[19]
In Iran, the mugger occurs along rivers in
Sistan and Baluchestan Provinces along the
Iran–Pakistan border.[2] A population of around 200 mugger crocodiles lives on the Iranian
Makran coast near
Chabahar. Due to human activity and a long
drought in the late 1990s and early 2000s, it had been pushed to the brink of
extinction. Following several
tropical cyclones in 2007 and 2010, much of the habitat of the mugger crocodiles has been restored as formerly dry lakes and
hamuns were flooded again.[24]
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.[25] In
Sindh Province, small mugger populations occur in wetlands of Deh Akro 2 and
Nara Desert Wildlife Sanctuaries, near
Chotiari Dam, in the
Nara Canal and around
Haleji lake.[26][27][28]
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.[50] It is possibly
locally extinct in the country.[51]
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.[34] It is considered locally extinct in
Myanmar.[2]
Behaviour and ecology
Mugger walking, Sri Lanka
Muggers basking on sand banks
The mugger crocodile is a powerful swimmer that uses its tail and hind feet to move forward, change direction and submerge. It belly-walks, with its belly touching ground, at the bottom of waterbodies and on land. During the hot dry season, it walks over land at night to find suitable wetlands and spends most of the day submerged in water. During the cold season it basks on riverbanks, individuals are tolerant of others during this period.
Territorial behaviour increases during the mating season.[20]
Like all crocodilians, the mugger crocodile is a
thermoconformer and has an optimal body temperature of 30 to 35 °C (86 to 95 °F) and risks dying of freezing or
hyperthermia when exposed to temperatures below 5 °C (41 °F) or above 38 °C (100 °F), respectively. It digs burrows to retreat from extreme temperatures and other harsh climatic conditions.[52] Burrows are between 0.6 and 6 m (2.0 and 19.7 ft) deep, with entrances above the water level and a chamber at the end that is big enough to allow the mugger to turn around.[20] Temperatures inside remains constant at 19.2 to 29 °C (66.6 to 84.2 °F), depending on region.[48]
Hunting and diet
The mugger crocodile preys on fish,
snakes,
turtles, birds and mammals including
monkeys,
squirrels,
rodents,
otters and
dogs. It also
scavenges on dead animals. During dry seasons, muggers walk many kilometers over land in search of water and prey.[53] Hatchlings feed mainly on insects such as
beetles, but also on
crabs and
shrimp and on
vertebrates later on.[54][55] 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.[56][57] Subadult and adult muggers favour fish, but also prey on small to medium-sized
ungulates up to the size of
chital (Axis axis).[58] 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.[30] Muggers have also been observed while preying and feeding on a
python.[55] At the Chambal River, muggers have attacked
water buffaloes,
cattle and
goats.[59]
In
Yala National Park, a mugger was observed killing a large
Indian pangolin (Manis crassicaudata), of which it devoured pieces over several hours.[60]
Tool use
Mugger crocodiles have been documented using lures to hunt birds.[61] 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.[62]
Reproduction
Female muggers obtain
sexual maturity at a body length of around 1.8–2.2 m (5 ft 11 in – 7 ft 3 in) at the age of about 6.5 years, and males at around 2.6 m (8 ft 6 in) 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 35–56 cm (14–22 in) deep holes for nesting between 1 and 2,000 m (3 ft 3 in and 6,561 ft 8 in) away from the waterside. They lay up to two
clutches with 8 –46 eggs each. Eggs weigh 128 g (4.5 oz) 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.[20][53]
Healthy hatchlings develop at a temperature range of 28–33 °C (82–91 °F). Sex ratio of hatched eggs depends on incubation temperature and exposure of nests to sunshine. Only females develop at constant temperatures of 28–31 °C (82–88 °F), and only males at 32.5 °C (90.5 °F). Percentage of females in a clutch decreases at constant temperatures between 32.6 and 33 °C (90.7 and 91.4 °F), and of males between 31 and 32.4 °C (87.8 and 90.3 °F). Temperature in natural nests is not constant but varies between nights and days. Foremost females hatch in natural early nests when initial temperature inside nests ranges between 26.4 and 28.9 °C (79.5 and 84.0 °F). The percentage of male hatchlings increases in late nests located in sunny sites.[63] Hatchlings are 26–31 cm (10–12 in) long and weigh 75 g (2.6 oz) on average when one month old. They grow about 4.25 cm (1.67 in) per month and reach a body length of 90–170 cm (35–67 in) when two years old.[20]
The
Bengal tiger (Panthera tigris tigris) occasionally fights mugger crocodiles off prey and rarely preys on adult mugger crocodiles in Ranthambore National Park.[70] 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.[71]
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.[2]
Major wetlands in Pakistan were
drained in the 1990s by dams and channels to funnel natural streams and
agricultural runoffs into rivers.[34]
In Gujarat, two muggers were found killed, one in 2015 with the tail cut off and internal organs missing; the other in 2017, also with the tail cut off. The missing body parts indicate that the crocodiles were sacrificed in
superstitious practices or used as
aphrodisiacs.[72]
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.[36] In 2017, a dead mugger was found on a railway track in Rajasthan.[73]
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.[2]
In India, it has been protected since 1972 under Schedule I of the
Wildlife Protection Act, 1972, which prohibits catching, killing and transporting a crocodile without a permit; offenders face
imprisonment and a
fine.[65]
In Sri Lanka, it was listed in Schedule IV of the Fauna & Flora Protection Ordinance in 1946, which allowed for shooting one crocodile with a permit. Today, it is strictly protected, but
law enforcement in Sri Lanka is lacking.[74]
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.[75]
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.[55][76] 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.[75]
A total of 1,193 captive bred muggers were released to restock populations in 28 protected areas in India between 1978 and 1992. Production of new offspring was halted by the Indian Government in 1994.[2]
In culture
The
Sanskrit word मकर '
makara' refers to the crocodile and a mythical crocodile-like animal.[77] The
Hindi word for crocodile is मगर 'magar'.[78] In English language, both names 'mugger' and 'magar' were used around the turn of the 20th century.[79][80][81] The names 'marsh crocodile' and 'broad-snouted crocodile' have been used since the late 1930s.[82]
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.[86] The
Muslim saint
Pīr Mango 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.[87] 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.[88]
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.[89] Fatal attacks of mugger crocodiles on humans were documented in Gujarat and Maharasthra, but they rarely consumed the victims who died of
drowning.[90]
A fable from the
Jataka tales of Buddhist traditions features a clever monkey outwitting a crocodile.[91] Three folktales feature crocodiles and
jackals.[92][93][94] A mugger crocodile is one of the characters in The Undertakers, a chapter of The Second Jungle Book.[79] The
children’s bookAdventures of a Nepali Frog features the character Mugger, the crocodile who lives by the Rapti River in Chitwan National Park.[95]
^Lesson, R. (1834).
"Le Crocodile des Marais". In Bélanger, C.; Geoffroy Saint-Hilaire, I.; Lesson, R.; Valenciennes, A.; Deshayes, G.P.; Guerin, F. E. (eds.). Voyage aux Indes-Orientales par le nord de l'Europe. Vol. Zoology. Paris: Bertrand. pp. 305–307.
^
abGray, J. E. (1844).
"Crocodiles". Catalogue of the tortoises, crocodiles, and amphisbænians, in the collection of the British Museum. London: Trustees of the British Museum. pp. 58–63.
^Lydekker, R. (1886). "Siwalik Crocodilia, Lacertilia, and Ophidia". Palaeontologia Indica. 10. Indian Tertiary and post-Tertiary vertebrata. Vol. III. Calcutta: Geological Survey Office. pp. 209–240.
^Garg, R. L. (1988). "New fossil reptile from the Siwalik Fossil Park, Saketi, Sirmur District, Himachal Pradesh". In Sastry, M. V. A.; Sastri, V. V.; Ramanujam, C. G. K.; Kapoor, H. M.; Rao, B. R. J.; Satsangi, P. P.; Mathur, U. B. (eds.). Symposium on three decades of developments in palaeontology and stratigraphy in India. 11. Calcutta: Geological Survey of India Special Publication. pp. 207–211.
^Shankar, K. & Rao, C. V. N. K. (1994). "First report of a fossil marsh crocodile Crocodylus palustris from the Manneru Valley, Andhra Pradesh". Current Science. 67 (9/10): 687–689.
JSTOR24095837.
^Iijima, M.; Takai, M.; Nishioka, Y.; Thaung-Htike; Zin-Maung-Maung-Thein; Egi, N.; Kusuhashi, N.; Tsubamoto, T.; Kono, R. T. & Hirayama, R. (2021). "Taxonomic overview of Neogene crocodylians in Myanmar". Journal of Vertebrate Paleontology. 41 (6): e1879100.
doi:
10.1080/02724634.2021.1879100.
S2CID233619370.
^Meredith, R. W.; Hekkala, E. R.; Amato, G. & Gatesy, J. (2011). "A phylogenetic hypothesis for Crocodylus (Crocodylia) based on mitochondrial DNA: Evidence for a trans-Atlantic voyage from Africa to the New World". Molecular Phylogenetics and Evolution. 60 (1): 183–191.
doi:
10.1016/j.ympev.2011.03.026.
PMID21459152.
^
abcdDa Silva, A. & Lenin, J. (2010).
"Mugger Crocodile Crocodylus palustris"(PDF). In Manolis, S. C. & Stevenson, C. (eds.). Crocodiles: Status Survey and Conservation Action Plan (3rd ed.). Darwin: IUCN Crocodile Specialist Group. pp. 94–98.
^Siddiqui, R.; Jeyamogan, S.; Ali, S. M.; Abbas, F.; Sagathevan, K. A. & Khan, N. A. (2017). "Crocodiles and alligators: Antiamoebic and antitumor compounds of crocodiles". Experimental Parasitology. 183: 194–200.
doi:
10.1016/j.exppara.2017.09.008.
PMID28917711.
^Mobaraki, A. & Abtin, E. (2013). "Estimate of Mugger population in Iran". Crocodile Specialist Group Newsletter. 32 (1): 11–21.
^
abKhadka, B. B.; Maharjan, A.; Thapalia, B. P. & Lamichhane, B. R. (2014). "Population Status of the Mugger in Chitwan National Park, Nepal". Crocodile Specialist Group Newsletter. 33 (3): 9–12.
^Nair, T. & Katdare, S. (2013). "Dry-season assessment of gharials (Gavialis gangeticus) in the Betwa, Ken and Son Rivers, India". World Crocodile Conference. Proceedings of the 22nd Working Meeting of the IUCN-SSC Crocodile Specialist Group. Gland: IUCN Crocodile Specialist Group. pp. 53–65.
^Taigor, S. R. & Rao, R. J. (2010). "Habitat features of Aquatic animals in the National Chambal Sanctuary, Madhya Pradesh, India". Asian Journal of Experimental Biological Sciences. 1 (2): 409–414.
^Joshi, R. (2013). "Range extension of mugger crocodile Crocodylus palustris (Lesson, 1831) in upper Ganges and tributaries, lesser Himalayan zone, north India". Journal of Biology and Earth Sciences. 3 (1): 100–109.
^Patil, S. R.; Atigre, R. H. & Patil, S. V. (2012). "First Record of Mugger Crocodile Crocodylus Palustrius (Lesson, 1831) from River Kadavi at Sarud, Tal, Shahuwadi, Dist. Kolhapur, MS, India". 4th International Conference on Agriculture and Animal Science. 47: 100–104.
^Sivaperuman, C. & Jayson, E. A. (2013). "An assessment of human-crocodile conflicts in Neyyar Wildlife Sanctuary, India". World Crocodile Conference. Proceedings of the 22nd Working Meeting of the IUCN-SSC Crocodile Specialist Group. Gland: IUCN Crocodile Specialist Group. p. 115.
^Whitaker, N. & Srinivasan, M. (2020). "Human crocodile conflict on the Cauvery river delta region, Tamil Nadu, south India". International Journal of Fisheries and Aquatic Studies. 8 (5 Part A): 1–5.
^Halder, N. K. (2003). Crocodile Conservation Plan of the Sundarban Forest (Report). Dhaka: Ministry of Environment and Forests, Government of Bangladesh.
^Lang, J. W. (1987). "Crocodilian behaviour: implications for management". In Webb, G. J. W.; Manolis, S. C.; Whitehead, P. J. (eds.). Wildlife Management: Crocodiles and Alligators. Sydney: Surrey Beatty and Sons. pp. 273–294.
^
abcBhatnagar, C. & Mahur, M. (2010). "Observations on feeding behavior of a wild population of marsh crocodile in Baghdarrah Lake, Udaipur, Rajasthan". Reptile Rap. 10: 16−18.
^Rao, R. J. & Gurjwar, R. K. (2013).
"Crocodile human conflict in National Chambal Sanctuary, India". World Crocodile Conference. Proceedings of the 22nd Working Meeting of the IUCN-SSC Crocodile Specialist Group. Gland: IUCN Crocodile Specialist Group. pp. 105–109.
^Dinets, V.; Brueggen, J. C. & Brueggen, J. D. (2013). "Crocodilians use tools for hunting". Ethology, Ecology and Evolution. 1: 74–78.
doi:
10.1080/03949370.2013.858276.
S2CID84655220.
^Venugopal, P. D. (2006). "Observations on Mugger Crocodylus palustris Lesson feeding on birds in Ranganthittu Bird Sanctuary, Karnataka, India". Journal of the Bombay Natural History Society. 103 (1): 105.
^Singh, L. A. K. & Kar, S. K. (2006). "Status of the Saltwater Crocodile in Orissa: An Overview". Journal of the Bombay Natural History Society. 103 (2–3): 274–285.
^Hornaday, W. T. (1901).
"V. The Gangetic Crocodile". Two years in the jungle : the experiences of a hunter and naturalist in India, Ceylon, the Malay Peninsula and Borneo (Seventh ed.). New York: Charles Scribner's Sons. pp. 55–57.
^Lydekker, R. (1901).
"Indian crocodile". The New Natural History. Vol. 5. New York: Merrill & Baker. p. 2378.
^Smith, W. L. (1992). "Some hagiographical motifs in the Śaṅkaravijayas". Wiener Zeitschrift für die Kunde Südasiens / Vienna Journal of South Asian Studies. 36, Supplement Proceedings of the VIIIth World Sanskrit Conference Vienna 1990: 189–195.
JSTOR24010818.
^Burton, R. F. (1877). "IV. Clifton, Ghisri Bandar, The Alligator Tank". Sind revisited. Vol. 1. London: Richard Bentley and Son. pp. 82–106.
^Crooke, W. (1906). "Crocodile". Things Indian: Being Discursive Notes on Various Subjects Connected with India. London: John Murray. pp. 111–113.
^Fischer, E. & Shah, H. (1971). Mogra Dev, Tribal Crocodile Gods: Wooden Crocodile Images of Chodhri, Gamit, and Vasava Tribes, South Gujarat (India). Art for tribal rituals in South Gujarat. Ahmedabad: Gujarat Vidyapith.
^Sideleau, B. & Britton, A. R. C. (2012).
"A preliminary analysis of worldwide crocodilian attacks". Crocodiles: Proceedings of the 21st Working Meeting of the IUCN–SSC Crocodile Specialist Group. Gland: IUCN/SSC Crocodile Specialist Group. pp. 22–25.