The southern river terrapin (Batagur affinis), popularly known in Cambodia is the “Royal Turtle”, belongs to the Geoemydidae turtle family, and comprises of two subspecies. These are the Batagur affinis affinis and the Batagur affinis edwardmollis. The Southern river terrapins possess a large body, thick limbs and fully webbed feet. Females and juvenile southern river terrapins are usually drably colored with a brownish to grayish carapace, while the males exhibit color changes, going from dark olive brown in the non-breeding season to a jet black color in the breeding season. The color of the iris of males also change from yellowish cream color to white during this time.
Eggs Fit for Royalty
The Southern River terrapins exhibit a highly interesting egg laying activity whereby they first dig a pit in the sand by using both their hind and forelegs and then settle down in the pit. Next they use their hind legs to form a nest cavity where they lay their eggs. An average of 26 eggs are laid per clutch by the female. Once done with egg laying, the turtle covers up the site with sand and even sits on the covered pit to make the sand covering more compact. Before leaving, the turtle digs a nearby sand pit, similar in appearance to its nest and in a manner that the sand dug out from this pit splashes down on the previous pit. The whole arrangement is to ensure that predators are confused when they arrive at the site and are unable to detect the original nesting site. The pounding sound made by the turtles while digging the pits gives them the local name of tuntung. Prior to the poaching incidents associated with these turtles and the rampant use of these turtle eggs for local consumption, the Southern River terrapins were protected by royal decree in Cambodia and Malaysia where the adults were protected against poaching and the eggs were only meant to be consumed by members of the royal households of the region. This helped conserve the turtles and also gave them their designation as “the Royal Turtles”.
Southern River Terrapin Life Cycle
The Southern River terrapin breeds and nests during the dry season, possibly breeding between October and February and nesting between November to March, when the female lays eggs on nesting beaches. Not much data is available regarding the nesting frequency of females and the number of clutches laid per year but some vague reports have suggested that 2-3 clutches of eggs are laid by the female per nesting season. The incubation period of eggs is heavily influenced by the surrounding temperature and decreases with increase in temperature. Usually, eggs of Southern River terrapins in Cambodia have an incubation period of 119 to 123 days. Once hatched, the hatchlings directly enter the water of the tidal estuaries and start migrating downstream into the ocean. Very little data also exist on the age at which these turtles attain sexual maturity. Some estimates indicate that the turtles attain sexual maturity at about the age of 25.
Threat of Extinction
The Southern River terrapins are currently heavily exploited by humans for their flesh and eggs. Large numbers of these species are poached for their flesh which is considered a delicacy in China. There are also reports that these turtles are captured to extract eggs where they are beaten heavily on their shells to induce them to drop their eggs or hung upside down for the same purpose. Besides poaching, the turtles also face great dangers from other anthropogenic activities, including the construction of dams, fishing, habitat destruction, deforestation, sand mining, and beachfront development. The construction of dams downriver from the nesting sites prevent the successful migration of these turtles and hatchlings between nesting and feeding sites. Thousands of turtles are also caught as part of by-catch in fishing operations. Sand mining activities and constructions on nesting sites destroy the eggs of the turtles and discourages the peaceful nesting of these creatures.
Today, the Cambodian Royal Turtle population is only about 10 individuals. Thus, this indicates that without significant implementation of conservation efforts, the turtles will soon vanish from the world. Several measures have been taken to conserve these animals like protection of the nesting sites as reserves where no form of human intervention is allowed, laws protecting the turtles against poaching and ex situ conservation efforts to save these animals. Eggs have been collected from vulnerable sites and allowed to hatch under protection in protected areas and then released into the wild. However, as per the recent rate of extinction of these turtles, it appears that these conservation efforts are insufficient, necessitating a further round of efforts to boost conservation of these animals.