False gharial
Encyclopedia
The false gharial also known as the Malayan gharial, false gavial, or Tomistoma is a freshwater crocodile
of the Crocodylidae family with a very thin and elongated snout. The false gharial is listed as an endangered species
by IUCN as the population is estimated at below 2,500 mature individuals.
Adult males weigh 150 to 250 kg (330.7 to 551.2 lb), while females are about 3.2 m (10.5 ft) long and weigh an average of 90 kg (198.4 lb).
, Sarawak
, Sumatra
and Borneo
, but extirpated in Thailand
. In the 1990s, information and sightings were available from 39 localities in 10 different river drainages, along with the remote river systems of Borneo. Apart from rivers, they inhabit swamps and lakes.
Prior to the 1950s, Tomistoma occurred in freshwater ecosystems along the entire length of Sumatra east of the Barisan Mountains
. The current distribution in eastern Sumatra has been reduced by 30-40% due to hunting, logging, fires and agriculture.
, i.e. only fish and very small vertebrates, but new evidence and occurrences have proven that the false gharial's broader snout has enabled larger individuals to prey on larger vertebrates including Proboscis monkeys, long-tailed macaques, deer and fruit bat
s.
At the end of 2008, a ±4 m female false gharial attacked and swallowed a fisherman in central Kalimantan
, whose remains were found in the gharial's stomach.
It is not known when they breed in the wild or when the nesting season is. Once the eggs are laid, and construction of the mound is completed, the female abandons her nest. Unlike most other crocodilian species, the young receive no parental care and are at risk of being eaten by predators like mongoose
s, big cat
s such as tiger
s and leopard
s, civet
s, and wild dogs
. The young hatch after 90 days and are left to fend for themselves.
s. The species is also hunted frequently for its skin and meat, and the eggs are often harvested for human consumption.
Steps have been taken by the Malaysian and Indonesian governments to prevent its extinction in the wild. There are reports of some populations rebounding in Indonesia, yet with this slight recovery, mostly irrational fears of attacks have surfaced amongst the local human population.
Yayasan Ulin (The Ironwood Foundation) is currently attempting to manage a wetland area in East Kalimantan which is known to contain the gharials.
than was originally thought. Along with close fossil
relatives such as Maroccosuchus
, it is sometimes classed in the family Gavialidae.
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
of the Crocodylidae family with a very thin and elongated snout. The false gharial is listed as an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
by IUCN as the population is estimated at below 2,500 mature individuals.
Characteristics
The false gharial is a large crocodilian that averages a length of up to 3.5 to 5 m (11.5 to 16.4 ft) with an extremely long and slender snout. It is dark reddish-brown above with dark brown or black spots and cross-bands on the back and tail. Ventrals are grayish-white, with some lateral dark mottling. Juveniles are mottled with black on the sides of the jaws, body, and tail. The snout is smooth and unornamented, and 3 to 3.5 times the width at the base. All teeth are long and needle-like, interlocking on the insides of the jaws, and are individually socketed. The fingers are webbed at the base. Integumentary sensory organs are present on the head and body scalation. Scales behind the head are frequently a slightly enlarged single pair. Some individuals bear a number of adjoining small keeled scales. Scalation is divided medially by soft granular skin. Three transverse rows of two enlarged nuchal scales are continuous with the dorsal scales, which consist of 22 transverse rows of 6 to 8 scales, are broad at mid-body and extend onto the sides of the body. Nuchal and dorsal rows equals a total of 22 to 23 rows. It has 18 double crested caudal whorls and 17 single crest caudal whorls. The flanks have one or two longitudinal rows of six to eight very enlarged scales on each side.Adult males weigh 150 to 250 kg (330.7 to 551.2 lb), while females are about 3.2 m (10.5 ft) long and weigh an average of 90 kg (198.4 lb).
Distribution and habitat
False gharials are native to Peninsular MalaysiaPeninsular Malaysia
Peninsular Malaysia , also known as West Malaysia , is the part of Malaysia which lies on the Malay Peninsula. Its area is . It shares a land border with Thailand in the north. To the south is the island of Singapore. Across the Strait of Malacca to the west lies the island of Sumatra...
, Sarawak
Sarawak
Sarawak is one of two Malaysian states on the island of Borneo. Known as Bumi Kenyalang , Sarawak is situated on the north-west of the island. It is the largest state in Malaysia followed by Sabah, the second largest state located to the North- East.The administrative capital is Kuching, which...
, Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
and Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
, but extirpated in Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
. In the 1990s, information and sightings were available from 39 localities in 10 different river drainages, along with the remote river systems of Borneo. Apart from rivers, they inhabit swamps and lakes.
Prior to the 1950s, Tomistoma occurred in freshwater ecosystems along the entire length of Sumatra east of the Barisan Mountains
Barisan Mountains
The Bukit Barisan or the Barisan Mountains are a mountain range on the western side of Sumatra, Indonesia, covering nearly 1,700 km from the north to the south of the island. The Bukit Barisan range consists primarily of volcanoes shrouded in dense jungle cover, including Sumatran tropical pine...
. The current distribution in eastern Sumatra has been reduced by 30-40% due to hunting, logging, fires and agriculture.
Diet
Until recently very little has been known about the diet or behavior of the false gharial within the wild, but thanks to some research on the part of biologists details are slowly being revealed. It has come to the attention of biologists that the false gharial's diet is much more varied than they had originally thought. Until now the false gharial was thought to have a diet similar to its relative the true gharialGharial
The gharial , , also called Indian gavial or gavial, is the only surviving member of the once well-represented family Gavialidae, a long-established group of crocodilians with long, slender snouts...
, i.e. only fish and very small vertebrates, but new evidence and occurrences have proven that the false gharial's broader snout has enabled larger individuals to prey on larger vertebrates including Proboscis monkeys, long-tailed macaques, deer and fruit bat
Fruit Bat
Fruit Bat can refer to:* Megabats, a species of bat which eats fruit* Les "Fruitbat" Carter, guitarist of Carter the Unstoppable Sex Machine* Fruit Bats , an American band...
s.
At the end of 2008, a ±4 m female false gharial attacked and swallowed a fisherman in central Kalimantan
Kalimantan
In English, the term Kalimantan refers to the Indonesian portion of the island of Borneo, while in Indonesian, the term "Kalimantan" refers to the whole island of Borneo....
, whose remains were found in the gharial's stomach.
Reproduction
Tomistoma are mound-nesters. Females lay small clutches of 13 to 35 eggs per nest, and appear to produce the largest eggs of extant crocodilians. Sexual maturity in females appears to be attained at around 2.5 to 3 m (8.2 to 9.8 ft), which is large compared to other crocodilians.It is not known when they breed in the wild or when the nesting season is. Once the eggs are laid, and construction of the mound is completed, the female abandons her nest. Unlike most other crocodilian species, the young receive no parental care and are at risk of being eaten by predators like mongoose
Mongoose
Mongoose are a family of 33 living species of small carnivorans from southern Eurasia and mainland Africa. Four additional species from Madagascar in the subfamily Galidiinae, which were previously classified in this family, are also referred to as "mongooses" or "mongoose-like"...
s, big cat
Big cat
The term big cat – which is not a biological classification – is used informally to distinguish the larger felid species from smaller ones. One definition of "big cat" includes the four members of the genus Panthera: the tiger, lion, jaguar, and leopard. Members of this genus are the only cats able...
s such as tiger
Tiger
The tiger is the largest cat species, reaching a total body length of up to and weighing up to . Their most recognizable feature is a pattern of dark vertical stripes on reddish-orange fur with lighter underparts...
s and leopard
Leopard
The leopard , Panthera pardus, is a member of the Felidae family and the smallest of the four "big cats" in the genus Panthera, the other three being the tiger, lion, and jaguar. The leopard was once distributed across eastern and southern Asia and Africa, from Siberia to South Africa, but its...
s, civet
Civet
The family Viverridae is made up of around 30 species of medium-sized mammal, including all of the genets, the binturong, most of the civets, and the two African linsangs....
s, and wild dogs
Dhole
The dhole is a species of canid native to South and Southeast Asia. It is the only extant member of the genus Cuon, which differs from Canis by the reduced number of molars and greater number of teats...
. The young hatch after 90 days and are left to fend for themselves.
Threats
The false gharial is threatened with extinction throughout most of its range due to the drainage of its freshwater swamplands and clearance of surrounding rainforestRainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
s. The species is also hunted frequently for its skin and meat, and the eggs are often harvested for human consumption.
Conservation
The false gharial is listed on CITES Appendix I.Steps have been taken by the Malaysian and Indonesian governments to prevent its extinction in the wild. There are reports of some populations rebounding in Indonesia, yet with this slight recovery, mostly irrational fears of attacks have surfaced amongst the local human population.
Yayasan Ulin (The Ironwood Foundation) is currently attempting to manage a wetland area in East Kalimantan which is known to contain the gharials.
Taxonomy
From a morphological standpoint, it has been originally placed within the family Crocodylidae, but recent immunological studies suggest that it is more closely related to the gharialGharial
The gharial , , also called Indian gavial or gavial, is the only surviving member of the once well-represented family Gavialidae, a long-established group of crocodilians with long, slender snouts...
than was originally thought. Along with close fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
relatives such as Maroccosuchus
Maroccosuchus
Maroccosuchus is an extinct genus of tomistomine crocodilian from the early Eocene of Morocco....
, it is sometimes classed in the family Gavialidae.
External links
- Crocodile Specialist Group: Tomistoma schlegelii
- Tomistoma Task Force
- Saint Louis Zoo: False Gharial
- ARKive Images
- BBC News: 'Match-making' for rare male croc
- Tomistoma schlegelii - Description with photographs from captivity in Czech republic (in Czech)
- The Orangutan Foundation research centre being used for critical research on False gharial