Mugger

## Description

The mugger (Crocodylus palustris ) is a crocodile of medium to large size with the broadest snout of all the living members of the genus Crocodylus. It lives in the Indian subcontinent as well as other countries in southern Asia. Like most crocodilians, muggers feature a flat head where their eyes, ears, and nose are on top. This enables them to see, hear and breathe above water when their bodies are underwater. The mugger 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.

## Appearance

The Mugger crocodile has the broadest snout among living crocodiles. It has a powerful tail and webbed feet. Its visual, hearing, and smelling senses are acute. 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 are well separated from the back. Scutes usually form 4, rarely 6 longitudinal series and 16 or 17 transverse series. The limbs have keeled scales with serrated fringes on the outer edges, and the outer toes are extensively webbed.

## Distribution

The mugger crocodile occurs in the Indian subcontinent as well as surrounding countries: Sri Lanka in the east, Iran in the west, and also Pakistan and Nepal. This species is found in freshwater lakes, marshes, and ponds, and has also adapted well to reservoirs, human-made ponds, irrigation canals, and coastal saltwater lagoons. This crocodile likes shallow water no more than 5 m deep, and it avoids fast-flowing rivers. It will sometimes bury itself in the mud to avoid the searing heat in India in the dry season.

## Behavior

Muggers are highly social and their social behavior includes gregarious behavior, communication, territorial activities, and dominance interactions. Between adults and also adults and their young, there are many vocalizations. Most of the socializing takes place during the seasonal mating activities. Body postures like snout raising and tail thrashing are used by males when establishing territories and trying to gain dominance before courtship and mating. Like other crocodile species, activities include basking, diving, and swimming. In addition, a unique and important activity is burrowing. Burrows are used for thermoregulation during hot and cold periods of the day and at night muggers come out to seek food. During dry seasons, muggers walk many kilometers overland in search of water and prey and they can chase prey for short distances on land. They are adapted better than most other crocodiles to life on land.

## Diet

Muggers are primarily carnivorous, eating mostly fish, frogs, crustaceans, insects, mammals, birds, and sometimes monkeys and squirrels. They also scavenge on dead animals.

## Reproduction

Mugger crocodiles exhibit a polygynous mating system, in which one male mates with more than one female. Breeding is from February to April. This species is a hole-nesting one. Once a female finds a suitable place for digging her nesting hole, she usually uses it for most if not all of her nests over the years. About one month after mating, 10-48 eggs are laid into the nesting hole, with the average clutch size being 28. Muggers sometimes lay two clutches a year in captivity, but it is not known what happens in the wild. Incubation is for 55-75 days. On hatching, the eggs are carried to nearby water by the mother or sometimes the father. Young crocodiles stay in loosely organized groups along with the adults for as long as one year before dispersing. The females reach maturity at around 6 years old when they are 1.7-2 meters in length, and males are mature at about 10 years old, at 2.6 meters.

## Population

### Population threats

The main threats to this animal come from the destruction of its habitat and illegal hunting for its skin and for the alternative medicine market. Another threat is egg collection. These crocodiles are also notorious fish stealers, eating ensnared fish, and sometimes they themselves become caught in fishnet and drown.

### Population number

According to the IUCN Red List, the total mugger crocodile population size is around 5,700-8,700 mature individuals. Specific populations have been estimated in these areas: 3,021 to 4,287 mature individuals in India; 200-300 individuals in Iran; around 600 individuals in Pakistan, with more than 150 individuals held in captivity; 200 wild individuals in Nepal; and around 2,400-3,500 wild individuals in Sri Lanka. Overall, currently, mugger crocodiles are classified as Vulnerable (VU), but their numbers today remain stable.

## Fun Facts

This animal’s scientific name of ‘Crocodylus palustris’ has the meaning “crocodile of the marsh”. This is aptly chosen since this species is very fond of the slow-moving waters that are typically found in marshy environments.

In Northern India this crocodile is so social that it can often be found living alongside another crocodile, the gharial.

The features of a mugger that define it as a crocodile include the fact that its top and bottom teeth overhang its closed mouth. The American alligator, in comparison, shows only its top teeth when its mouth is closed.

The webbed feet of crocodiles are not used to propel them through the water, but instead, allow them to make sudden moves and fast turns and to initiate swimming. Webbed feet assist the animal in shallower water where it sometimes walks around.

The only animals that are known to prey on mugger crocodile adults are other crocodiles and tigers.

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.