Image (c) Adam Britton, crocodilian.com
Order: Crocodylia
Family: Crocodylidae
Subfamily: Crocodylinae
Genus & Species: Crocodylus palustris
APPEARANCE
Mugger crocodiles are the most alligator-like of all the crocodiles in both appearance and habitat. They are fair-sized crocodiles, reaching maximum lengths of 16 ft (5 m) and having an average length of 13 ft (3.9 m). The males are generally larger than the females.
Mugger crocodiles have the broadest snouts of all the crocodiles, giving them the appearance of the American alligator. The head is relatively flat on the top, with the eyes, ears, and nostrils all being on the same plane. This allows the crocodile to see, hear, and smell while almost completely submerged underwater. The eyes are protected by a third eyelid called a nictitating membrane which is clear and keeps water out of the eye. The mouth contains 66-68 pointed teeth. These teeth are what distinguish mugger crocodiles from alligators, as mugger crocodile teeth are perfectly aligned and alligator teeth are not. The fourth tooth on either side of the bottom jaw is larger than the others and fit into a notch on the upper jaw, making these two teeth visible when the mouth is closed.
Mugger crocodiles are excellent swimmers, using their flat tail to propel them. Their feet are webbed, but are not used for swimming. The body is well protected by a tough, scaly skin. The neck has large scutes on it and resembles that of the American alligator. The juveniles are 10 inches (25 cm) long and are a light tan in colour, with black cross-bandings on the back and tail. The adults are grey to brown in colour with few cross-bandings.
Mugger crocodiles have life spans of 40+ years. They are highly social and communicate with a wide variety of vocalizations. They will also socialize with other crocodilian species, especially the gharial.
HABITAT
Mugger crocodiles are, or at one time were, found in Bangladesh, Iran, India, Sri Lanka, Nepal, Myanmar, and Pakistan. They are thought to be extirpated from Myanmar.
Mugger crocodiles are found basically in freshwater, including marshes, ponds, lakes, irrigation canals, and reservoirs, as well as saltwater lagoons. As the name "Crocodylus palustris", "crocodile of the marshes", suggests, they are found mainly in marshes, the same type of habitat as the American alligator. They are a highly adaptive species, being able to live in man-made pools of water. Mugger crocodiles like slow-moving, shallow water that is no deeper than 16 ft (5 m), making man-made irrigation canals the perfect habitat. During the dry season mugger crocodiles dig burrows in the mud to protect themselves from the heat, and they may travel long distances over land to find water if their pool of water dries up.
FOOD
Mugger crocodiles are large enough to have a very diverse appetite. The juveniles feed on invertebrates such as crustaceans and insects, and small vertebrates such as fish. Adults capture larger prey, such as fish, frogs, snakes, turtles, birds, and mammals such as squirrels, monkeys, deer, and buffalo.
ENEMIES
In the early 1800's there were said to be thousands of mugger crocodiles, and that the species was quite common throughout India. However, unregulated hunting of the skins brought the entire population to the brink of extinction. 1867 brought about the last sighting of a mugger crocodile in Myanmar. By the 1970's, awareness of the plight of crocodiles created protection for this species and many other crocodile species. Captive breeding brought the wild population up to 5000.
Habitat destruction is the main threat today, causing a 20% decline in numbers in the past few years. This habitat destruction is also creating less places to release captive-bred crocodiles. In 1994, there were several thousand captive mugger crocodiles with nowhere to go, and captive breeding has ended in some countries because of this. Today, the species is considered to be vulnerable.
BREEDING
Females reach sexual maturity at 6 years of age while males reach sexual maturity at 10 years. Females stay fertile until 30-years-old. Hole nests are dug in sloping banks, the side of burrows, or other areas near water and with loose soil, between the months of December and February. A month after mating, the female lays 10-48 eggs in the nest. After an incubation period of 55-75 days, the eggs hatch. The mother and father take the juveniles down to the water where they stay with adults for 1 year.
The temperature of the nest determines the sex of the juveniles: 32.5° C — the embryos are all males. Between 28-31°C — all females.
RELATIVES
The mugger crocodile is suggested to have one Sri Lankan subspecies, C. p. kimbula, but this has never been accepted.
RESOURCES CITED
1. www.flmnh.ufl.edu/natsci/herpetology/brittoncrocs/csp_cpal.htm
2. www.flmnh.ufl.edu/natsci/herpetology/act-plan/cpalu.htm
3. www.hort.agri.umn.edu/h5015/99/papers/jacobson.htm
4. animaldiversity.ummz.umich.edu/accounts/crocodylus/c_palustris.htm
5. www.pbs.org/wgbh/nova/crocs/whos/nojs.html#17
6. www.herper.com/GDHS1.html
7. www.webcom.com/~iwcwww/volunteers/nov99/spec_pg5.htm
8. www.pakcenter.com/reading/education/zoo/reptiles/rep8.html
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