The Southern River Terrapin (Batagur affinis) is a member of the Geoemydidae family, one of the most diverse groups of freshwater turtles, with over 70 recognised species worldwide (Clemente et al., 2021). Batagur affinis is native to Southeast Asia and is found in Malaysia, Southern Thailand, Cambodia and Vietnam.
In Malaysian local communities, Batagur affinis is generally known as Tuntung Sungai because of the gentle "tung tung" sound it makes. This species inhabits major river systems in the states of Perak, Kedah, and Terengganu, while in Borneo, it is mainly found in Sarawak. The carapace (upper shell) of adult species is between 43.1 cm and 62.5 cm long (Moll et al., 2015). The shell is deep, large and strongly buttressed (Xuan, 2024). Like other freshwater turtles, it possesses fully webbed feet and powerful limbs. This species can be distinguished by having only four claws per limb, rather than five as seen in many other riverine turtles. Males can be recognised by their darker head colouration, bright yellow eyes, longer and thicker tails, as well as a more concave plastron (bottom shell), features that differentiate them from females. According to Platt et al. (2021), females are significantly larger than males, with some individuals weighing up to 36 kg, while fully developed adults typically range between 20 and 25 kg.
This species feeds mainly on plant sources such as fallen fruits and aquatic plants, but its diet may also include animal proteins like molluscs, prawns, and small fish. This feeding behaviour indicates that this species is omnivorous, especially in natural river systems where food availability varies seasonally.
One of the most remarkable features of the Southern River Terrapin is its reproductive pattern. Unlike many freshwater turtles that produce around 110 eggs per season, B. affinis only lays 25–30 eggs during a single breeding season, which typically occurs in the dry months between November and March (Moll et al., 2015). Another important behavioural trait is natal homing, where the females would return to the same nesting beaches to lay their eggs, year by year. This behaviour contributes to maintaining stable population distribution patterns.
Southern river terrapins are also known for their cautious and elusive behaviour. They tend to avoid human presence and retreat when disturbed by noise or activity near their nesting areas, making them difficult to observe in the wild (Chen, 2017). Despite their quiet and elusive nature, the Southern River Terrapin plays a vital ecological role. As it moves through the water and along riverbanks, it helps regulate vegetation growth and prevents river habitats from becoming overgrown by feeding on aquatic plants and fruits (Mohd Salleh et al., 2022). The species also facilitates seed dispersal, supporting the regeneration of riparian plants, while its nesting activities contribute to soil aeration and the nutrient cycling process.
According to IUCN (Horne et al., 2019), the species is classified as Critically Endangered (CR), indicating that it faces an extremely high risk of extinction in the wild. Populations have been severely impacted by egg collection, habitat destruction (including sand mining), poaching and other environmental pressures. Various conservation initiatives are being implemented to protect this iconic species from extinction, including habitat restoration, nest protection programmes, captive breeding programmes and community-based awareness activities.
