False gharial, Malayan gharial, Sunda gharial, False gavial, Falso gavial malayo, Faux gavial malais, Baja (Baya) Kanulong, Bediai Sampit, Boeaja, Buaja, Buaya, Buaya Jolong-Jolong, Buaya Sa(m)pit, Buaya Senjulong, Buaya Sepit, Jolong-Jolong, Malay gavial
The tomistoma (Tomistoma schlegelii) is a freshwater crocodalian native to Southeast Asia. The tomistoma has quite an unusual appearance and about this species, there is not much information. It has one of the slimmest snouts of any living crocodilian, comparable to that of the Slender-snouted crocodile and the Freshwater crocodile in slenderness; only that of the gharial is noticeably slimmer.
The tomistoma 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 smooth and unornamented snout is extremely long and slender, parallel-sided, with a length of 3 to 3.5 times the width at the base. The tomistoma apparently has the largest skull of any extant crocodilian, in part because of the great length of the slender snout. All teeth are long and needle-like, interlocking on the insides of the jaws, and are individually socketed. The dorsal scales are broad at midbody and extend onto the sides of the body. The digits 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 midbody and extend onto the sides of the body. Nuchal and dorsal rows equal a total of 22 to 23 rows. It has 18 double-crested caudal whorls and 17 single-crested caudal whorls. The flanks have 1 or 2 longitudinal rows of 6 to 8 very enlarged scales on each side.
Historically these reptiles lived in South East Asia in the Malay Peninsula and on Borneo and Sumatra. Today in Thailand it seems to be extinct and is seen at low densities only (although the populations are widespread) in Indonesia and Malaysia. They may have been seen in Vietnam and Sulawesi. They inhabit freshwater swamps, lakes, and rivers, preferring water that is slow-moving, and heavily vegetated habitats.
The tomistoma is solitary and can be active at any time of the day or night. It spends most of its time submerged in mud-holes or shallow wallows, with only its eyes and nostrils showing. Basking behavior, though not often observed, is probably used to aid thermoregulation. They may sometimes occupy burrows. The size of their home range and their territorial behaviors in the wild are not known. In captivity, many males and females are able to be housed in one enclosure with no obvious aggression. Communication between tomistoma individuals has not been reported in the wild. From observation of mating behaviors, it is assumed that they communicate through sight, touch, and smell. Most crocodilians use a range of calls for communication purposes, but these have not been observed for tomistoma, and any mating behavior has been seen to be silent.
Tomistoma are opportunistic carnivores and sometimes grab monkeys (such as crab-eating macaques) from river banks, drowning their victim or beating it against a bank of the river. They also eat wild pigs, mouse deer, otters, fish, birds, turtles, dogs, snakes, monitor lizards, terrestrial and aquatic invertebrates.
There is little knowledge about the natural mating behavior of false gharials, with most details from captive breeding programs, and only a few accounts about wild individuals. Crocodilians are typically polygynous, and males attempt to mate with multiple females. Breeding is from November to February and April to June, which are the wet seasons. These are mound-nesting crocodilians, and they usually build their mound on land near water at the base of a shady tree, using sand and a variety of vegetation such as peat, twigs, dried leaves, and tree seeds. 20-60 eggs are laid and then the mother adds extra vegetation on the top of her nest. Mounds are usually 90-110 cm wide and 45-60 cm high. The incubation period is 90-100 days. Breeding in captivity has shown that a lot of vegetation improves breeding chances because there is more cover and material for nesting available to the female. The young are given no parental care when they hatch and must look after themselves. They reach reproductive maturity at about 20 years of age.
Habitat destruction as a result of such ongoing activities as the construction of dams, deforestation, and channeling has been the major cause of this species’ decline. In addition, intensive hunting in the mid-20th century in some regions, especially Sumatra, also greatly impacted this species. Further threats are from fishing practices, where tomistoma can be caught in nets or poisoned by the toxins used for killing fish, and they are also in competition for the same food source as local fishermen.
According to the IUCN Red List, the total tomistoma population size is around 2,500-10,000 mature individuals. Currently, this species is classified as Vulnerable (VU) and its numbers today are decreasing.