Species Spotlight Vol. 14
by Jordan Gray
Southern River Terrapin (Batagur affinis)
Countries of Origin: Cambodia, Indonesia (Sumatra, likely extirpated), Peninsular Malaysia, Singapore (reintroduced), Thailand (likely extirpated), and Vietnam (extirpated)
IUCN Status: Critically Endangered
Estimated surviving population: < 500 adults. Only two actively-protected nesting areas of value remain in the wild.
Habitat: Large rivers, mangrove-bordered creeks, and coastal lagoons and estuaries.
Biology and Habits: The Southern River Terrapin is an herbivorous species, feeding on aquatic vegetation, low overhanging riparian vegetation, and fruits. Females nest on sand bars and sandy beaches, sometimes traveling up to 80 km (50 mi) between their foraging grounds and nesting site. They may lay up to three clutches per year containing between 5 to 38 eggs per clutch.
Size: Males ~ 49 cm (19 in), Females ~ 60 cm (24 in)
- The Southern River Terrapin is divided into two subspecies: Batagur affinis affinis and Batagur affinis edwardmolli.
- This species is colloquially called "tuntung" in Malaysia and "tuntong" in Indonesia.The names derive from the reverberating sound made by the turtle's plastron as the female packs its nest with sand following egg laying. "The turtles' tamping action sounds like drums playing primeval staccato rhythms." - Mittermeier et al.
- The Southern River Terrapin, known commonly as "Royal Turtle," was declared the National Reptile of Cambodia by decree in 2005.
- The common name of "Royal Turtle" derives from the account that this species' eggs are considered a delicacy and aphrodisiac. During the 19th and early 20th centuries, nesting areas were protected from general exploitation and egg collection and consumption was reserved for royalty.
- This species exhibits marked sexual dimorphism (morphological differences between males and females) in the form of sexual dichromatism (color differences between males and females). While females remain in a muted state of coloration throughout the year, the pigment melanin is hyper-expressed in males during the breeding season, giving them an overall dark grey to black appearance. The melanin expression is especially pronounced on the head and neck region; starkly contrasted by golden-yellow eyes.
- In parts of this species' range, the adult turtles are protected from consumption as "haram" by Islamic law, the predominate religion of Malaysia. This haram however does not protect the eggs of the species, and over collection of the eggs has resulted in a massive reduction in the recruitment of new turtles into the population. Furthermore, as non-Muslims began populating the region in larger numbers after World War II, the "haram" no longer gave the species the widespread protection it once had in those areas.
- The aftermath of wars and regime changes have had a significant impact on this species. During World War II, the Southern River Terrapin was heavily harvested to feed the Japanese soldiers occupying the region. Additionally, untold numbers of this species were collected for market following the fall of the Khmer Rouge communist regime in Cambodia.
Greatest Threats: Valued for its meat and eggs, the Southern River Terrapin has been overexploited throughout its range. Additionally, habitat destruction and alteration, sand mining, incidental drowning in fish nets, and the building of hydroelectric dams have significantly compounded the anthropogenic threat to this turtle. Of these, sand mining is the largest current threat, greatly impacting the availability and integrity of nesting areas. This species has seen a population reduction of greater than 90% in its historical numbers in just the last 75 years. With less than 1% of its historical numbers remaining in the wild, this species is at high-risk for functional and ecological extinction.
How you can help: The Turtle Survival Alliance (TSA), Wildlife Conservation Society (WCS), Royal Government of Cambodia's Fisheries Administration (FiA), Rainforest Trust, and Mandai Nature are collaborating to help protect and restore a relict population of the Eastern Malay River Terrapin in the Sre Ambel River system of Cambodia. You can directly aid this effort by supporting these organizations.
Photo credit: Eng Heng Chan