An ancient freshwater species dating back to the Eocene epoch (about 55 million years ago), Tomistoma are commonly found in lakes, swamps, rivers, and wetlands. They prefer slow moving water with an abundance of forest vegetation in their habitat, and are commonly seen in freshwater swamp forests and peat swamps.

Tomistoma are native to Indonesia and Malaysia. They can be found in eastern Sumatra, Kalimantan, Western Java, parts of Peninsular Malaysia, and Sarawak. They once occurred in Thailand; however, as there have been no recorded sightings since 1970s, they are sadly considered extinct in this location.

Tomistoma hatch out of the largest egg of any living crocodilian species! Fewer than 20 nests have been recorded in the wild thusfar, so we have very limited information on Tomistoma reproductive behaviour. A clutch normally consists of anywhere between 13-to-60 eggs; however, 90% of hatchlings die within their first year. Unusually for crocodilians, no evidence has been recorded of hatchlings receiving parental care.

With their streamlined muscular body and tail; eyes , ears, and nostrils positioned on top of their head; thick skin and scales reinforced with bony plates (known as osteoderms); and iconic long, narrow snout filled with up to 84 interlocking pointed teeth - they are perfectly adapted predators within their native environment. Furthermore, their osteoderms do not only serve as armour, but also as a kind of solar panel, enabling them to heat up more easily (warmth is essential for most reptiles to function and remain healthy).

To hunt, Tomistoma wait motionless in the water with their jaws open, waiting for fish (or other animals) to come within striking range. Their skin and scales contain special sensory organs, known as Dermal Pressure Receptors; these specialist receptors are adapted to sense movement in the water, which ultimately helps them to identify prey. They’re thought to have fantastic night-vision, too!

As hatchlings, they are born countershaded, with black bands on their tails and bodies, and dark blotches on their jaws. They retain much of this colouration as adults; however, they usually become lighter or reddish brown - particularly down their backs.

While females usually grow up to around 3 meters long (9.84 feet), males can reach an impressive 5 meters (16.4 feet) on average, with the largest recorded reaching up to 6 meters (19.7 feet).  Interestingly, female sexual maturity is determined by size, at around 2.5-to-3 meters (8-to-10 feet).

According to research (by Staniewicz, Foggett, McCabe, and Holderied, 2021), although generally silent, Tomistoma use underwater acoustic (sound) signals during times of distress, courtship and mating.

Unfortunately, Tomistoma is listed as Endangered on the IUCN Red List. This is predominantly due to severe and continuing loss and fragmentation of swamp forest habitat throughout their global range. Much of this is due to large-scale commercial and illegal logging, plantation development (especially palm oil, and paper pulp mills), forest fires, and deliberate swamp drainage through construction of channels and dykes.

Based on satellite imagery, it is estimated that more than 1-million hectares (over
2-million acres / over 107-billion square feet) of peat swamp has been converted to various land uses across Peninsular Malaysia and Thailand, Borneo and Sumatra respectively. To add to this, the introduction of wild pig (Sus scrofa) into Sumatra have also increased pressures on Tomistoma, as the wild pigs eat their eggs.

Tomistoma have also been known to drown after being accidentally caught in fishing gear; however, local fishermen are often known to rescue them, as it’s a local belief that harming Tomistoma will bring bad luck or illness. Overall, the impact of fishing on prey and habitat availability - and of the potential competition between fishermen and Tomistoma - is poorly understood.

As this species is naturally very shy, they have proven to be extremely difficult to observe in the wild. There is still so much that we don’t know about them! We hope that our camera traps may help with future research; knowledge which can be used to help this species recover and protect their habitat.