Crocodylus palustrisMugger crocodile, Swamp crocodile

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Geographic Range

The mugger is found primarily on the Indian subcontinent and extends into Pakistan and Sri Lanka.

Habitat

This species is not only found in freshwater lakes, ponds, and marshes, but it has adapted well to reserviors, irrigation canals, human-made ponds, and even recently in coastal saltwater lagoons. The mugger likes relatively shallow water, no deeper than 5m, and avoids fast-flowing rivers. The mugger is also known to bury itself into mud to escape the searing heat of India during the dry season.

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

Muggers are medium to large crocodiles, reaching 4 to 5 meters in length. Like all crocodiles, they have an elongate, robust skull and jaw musculature. They have the broadest snout of any living member of Crocodylus.

  • Average length
    4-5 m
    ft

Reproduction

This species of crocodile is a hole-nesting species. Once the female finds a suitable site to dig her nesting hole, it is usually utilized for most or all of her breeding years. Approximately one month after mating occurs, the eggs are deposited by the female into the nesting hole she has formed. This takes place in February-April and consists of an average 28 (10-48 range) eggs per clutch. The mugger has been known to lay two clutches in one year while being kept in captivity, but little is known about the individuals in the wild. The incubation period is relatively short, 55-75 days. When the eggs finally hatch, they are transported by the mother and sometimes even the father to nearby water. Young crocodiles remain in loosely organized groups with the adults for up to one year before dispersing.

Females reach sexual maturity at about 6 years old, from 1.7 to 2 meters in length. Males reach sexual maturity at around 10 years old, when they have reached lengths of 2.6 meters.

  • Breeding interval
    Muggers breed once each year.
  • Breeding season
    Breeding occurs from February to April.
  • Range number of offspring
    10 to 48
  • Average number of offspring
    28
  • Range gestation period
    55 to 75 days

Lifespan/Longevity

Adult muggers are long lived (20-40+ years), and have a longer than average reproductive length as well (10-30+ years).

Behavior

All crocodiles, including the mugger, are highly social. This social behavior includes communication, gregarious behavior, dominance interactions, and territorial activities. There is a great deal of vocalization between adults and adults and their young. The majority of socializing occurs during the seasonal reproductive activities. Body postures such as tail thrashing and snout lifting occur while the males are trying to establish territories and gain dominance prior to courtship and mating.

Food Habits

The mugger is mostly carnivorous with a diet consisting mainly of fish, frogs, crustaceans, birds, mammals, and occasionally various monkeys and squirrels.

Economic Importance for Humans: Positive

Crocodylus palustris is known to have close associations with Indian culture as a religious symbol and for use in indigenous medicines. Sport hunting of crocodiles was once very popular, as well as hunting crocodiles for their skin, a material that is widely used in shoes, handbags, and other luxuries.

Conservation Status

In the past (1950s-1960s), the main source of threat to Crocodylus palustris was illegal skin trading. Now, the current threats have changed to individuals drowning in fishing nets, egg predation by people, and habitiat destruction. There has been considerable progress with the management of crocodiles in India. The management of the mugger is based principally on the legal protection of wild populations and large scale captive rearing programs.

Other Comments

Mugger is derived from Hindi, while the alternative name: marsh crocodile stems from its scientific name, with palustris translating as 'of the marshes'. In Northern India the mugger is such a social crocodile that it is often found to be sympatric with another type of crocodile, Gavialis gangeticus.

Contributors

Stephanie Lammy (author), University of Michigan-Ann Arbor.

Glossary

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

References

Alderton, David. 1991. Crocodiles and Alligators of the World. Facts on File, New York.

Crocodile Specialist Group Working Meeting.1984. Crocodiles. IUNC, Caracas, Venezuela.

Webb, J.W. Grahame, Manolis, S. Charlie, and Whitehead, J. Peter. 1987. Wildlife Management: Crocodiles and Alligators. Surrey Beatty and Sons Pty Limited, Australia.

Thorbjarnarson, John. 1992. Crocodiles-An Action Plan for Their Conservation. IUNC, Gland, Switzerland.