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, also known as the false gharial, with a slender snout like the gharial, is an unusual crocodilian (a group that includes crocodiles, alligators, caimans and gharials), about which there is not much information. It lives in freshwater. Juveniles are dark or chocolate brown and have black banding on their tail and body, with dark blotches on their jaws and a creamy white belly. These colors are mostly the same in adulthood.
Historically these animals 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.
Habits and lifestyle
This species 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.
bask, congregation, float, nest
Diet and nutrition
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 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.
Fun facts for kids
- The scientific name ‘tomistoma’ has the meaning "sharp mouth", from ‘tomos’ (a Greek word for "cutting" or "sharp") plus ‘stoma’ (Greek for "mouth"), which refers to its slender jaws.
- Another scientific name for this species is ‘schlegelii’, which means "of Schlegel", with reference to H. Schlegel (1804-1884), the Dutch zoologist who discovered this species.
- All crocodilians have integumentary sense organs in the skin, covering much of their body including the tail, cloaca, the inner surfaces of their legs, head and jaws. They probably use these to detect any changes in pressure that are caused by touch or by the movement of their prey in the water, and is likely to be used when hunting in murky water.
- Crocodilians can stay underwater for a long time. They usually go under for 10-15 minutes, though they can stay submerged for up to 2 hours when they perceive a threat.
- Tomistoma females have sometimes been seen sitting on their nest mounds during the incubation period or defending the nest by stomping the ground, though usually they desert the nest if approached.