1 AnatomyH. grandis is sometimes called Orange Headed Temple Turtle, because it has orange spots on the face. The carapace has a single, well-shaped keel and spiny marginals.
The forelimbs are covered with scales, the toes are webbed.
The plastron is yellow with radiating dark lines on every plate. As the turtle grows older this pattern fades away. The anterior and posterior plastron are serrated. In adult females the plastron is slightly movable.
Plastral formula: abdominal femoral pectoral anal humeral gular (i.e. The interabdominal seam is the longest, then the interfemoral etc.)
The maximum size is up to 43,5 cm (17"); its maximum weight up to 12 kg (26,4 lbs).
H.grandis has 2n=52 chromosomes.
1.1 Sexing H.grandisIn contrast to most turtle species (sub-)adult female grandises are on average smaller than males, and have a shorter tail. Males usually have a concave plastron, and a thicker tail than females.
Hatchlings show no sexual dimorphism. The only indication of their gender is the temperature at which they have been incubated. It can take up to four years before you can determine their gender with certainty.
1.2 Distinguishing H.grandis from other speciesHeosemys spinosa is smaller and has a rounder shell. Its toes are only partially webbed. Juveniles have spines all around the shell.
Cyclemys species are smaller than H. grandis, and have a proportionally smaller head.
Cyclemys dentata doesn't have a bicuspid upper jaw. Adults have a plastral hinge.
Cyclemys tcheponensis has four stripes extending from the neck forward over the side of the head
• Heosemys identification key
• related forum topic
2.1 HabitatSwampy wetlands, deciduous forest and mountain streams. It spends much time on land partially hidden under shrubbery.
2.2 DistributionSouth Myanmar, southern Vietnam, Cambodia, Laos, central & west Thailand and peninsular Malaysia. There is not enough data to confirm its occurrence (past or present) in Singapore.
Protected in Thailand, Myanmar and Cambodia.
• Giant Asian pond turtles in the wild and in captivity, around the world
• Heosemys grandis in museum collections
• Distribution/Status of H. grandis in Singapore
2.3 Other turtle speciesH.grandis shares some of its natural habitat with Amyda cartilaginea, Indotestudo elongata, Manouria emys, Chitra chitra, Cuora amboinensis, Heosemys spinosa and (introduced) Trachemys scripta elegans, and can encounter any of these in the wild.
3 BehaviourThe species has been kept together with the following species, without any reported complications: Trachemys scripta elegans, Pelusios sinuatus, Chrysemys concinna, Cuora amboinensis, Cuora trifasciata, Batagur baska, Callagur borneoensis, Orlitia borneensis, Pseudemys rubriventris, Terrapene carolina, Rhinoclemmys pulcherrima, Rhinoclemmys diademata, Testudo hermanni & Ocadia sinensis. They are generally friendly to other species. However, some adult males can be very agressive and should be separated from all other turtles.
Unlike most other turtle species, H.grandis doesn't display any subtle courtship behaviour. They bite at the neck, legs and head of females. Quoting an expert: 'Males' idea of reproduction often skips courtship and goes straight down to business, regardless of the female's consent.'
4 HusbandryA vivarium for an (sub-)adult H.grandis should have a water area & a dry area with some hiding places. If the dry area doesn't have any hiding places, the turtle will stay in the water.
A maximum day temperature of 24C-28C is recommended, although H.grandis already feels happy with 12C. The temperature may vary to simulate the dry & wet seasons.
They are mostly aquatic as hatchlings. As they grow older, they become more terrestrial.
5 NutritionAccording to Peter Pritchard, 'this species eats almost anything edible', but wild animals feed mainly on fruit & aquatic plants. Recommended food products include: all kinds of (low fat) meat & fish, fruit, lettuce, aquatic plants like Elodea, Ceratophyllum, Azolla, Vallisneria. Giant Asian pond turtles don't eat live food and some don't like fish. Cuttlefish bone should always be available to them. Don't overfeed them, they easily get fat.
• dietary requirements of Asian turtles
• forum topics on feeding
6 BreedingWild animals in South East Asia nest at the end of the rainy season, late November-early December, and hatchlings emerge at the start of the next rainy season, May-June.
H. grandis lays 2-6 oval eggs (depending on the size of the female). The eggs are 55-65 mm in size and weigh 50-60 g.
Some females display nesting behaviour (wandering around & digging) after the actual egglaying.
In captivity, the eggs need an incubation period of three and a half to six months, at a temperature of 29C and 100% humidity. Hatchlings weigh about 23 g and have a large fontanelle or "soft spot" in the middle of the plastron.
• reference: Ernst/Barbour (1989)
• Incubation temperature and sex determination
6.1 HybridsThe Geoemydidae family is notorious for producing hybrids, but I don't know of any confirmed cases of a H.grandis hybrid. A Heosemys grandis x Ocadia sinensis hybrid has been mentioned on a Kingsnake-forum once (view source) but I have not been able to verify this.
7 Health issues
Heosemys grandis are reported to carry Entamoeba invadens, a common amoebic protozoan; Falcaustra kinsellai, Serpinema octorugatum, Oswaldocruzia malayan, Spironoura siamensis, Spironoura stewarti, Zanclophorus purvisi, Quasichorchis purvisi, Stunkardia dilymphosa and Telorchis clemmydis
• sources: Murray (2004), Sharma e.a. (2002) Bursey and Freeman (2005)