Heosemys grandis / Chinese woodturtle - Care

Heosemys grandis, (Gray, 1860)

The Giant Asian pondturtle lives up to the name. These turtles get big! The genus of Heosemys is placed under the family Geoemydidae. The genus consist of 4 recognised species, the previous fifth species, Heosemys leytensis was included in the Genus Siebenrockiella together with the Siebenrockiella grassicollis in 2005.

Other Heosemys and their current status:

1.Heosemys annandali; wish in captivity is only found in a few zoos and with private keepers that work together with conservation organisations. Cites excluded this species from export in 2002.

2.Heosemys depressa; an extremely rare species that lives only in the Arakan hills of western Myanmar and some in the bordering Chittagong Hill Tracts of Bangladesh. In captivity these are only represented by a small group distributed between a few Zoo’s.

3.Heosemys spinosa; wish is also listed as endangered by the IUCN and listed under the Cites Appendix II is although in small numbers represented in captivity. Ether in zoos or with private keepers. As Cites stopped exportation of this animal most animals in captivity are ether very old, from times when exporting was allowed or from confiscations and also captive bred although in relative small numbers.

4.Heosemys grandis, the species described in this article is probably the most kept and bred in captivity. Although also animals are rehomed after being confiscated from wildlife traffickers. All Heosemys species are heavily endangered by the Asian Food and medicine trade as well as for the pet trade. They are restricted from exporting and listed under Cites Appendix II. IUCN classifies this species as vulnerable.

Next to this article we can strongly recommend to make a visit to the Heosemys.org website. Which contains a lot of information about this interesting turtle.

General appearance:  Heosemys grandis is found in a wide range and therefor there seems to be some differences in the appearance depending on their origin. Hatchlings often have a slightly lighter colour. More pronounced vertebral keel and the marginal scutes are serrated although not as extreme as seen with young Heosemys spinosa. With adults these spiny marginal scutes are much less present to practically obsolete except in the hind courters. The average length is 30-34cm with a described maximum of 43.5cm and big full grown adults can weigh up to 10 kilograms but normally weight between 3 till 5 kilograms.

Their body colour is a dark brown or grey. On their head there are a lot of orange markings. In some individuals these markings can be very faint till non-existent. They have big strong legs and the front legs have a lot of big scales. They have webbing between their toes to help with the movement in the water. Their shell or carapax is a typical oval and low form wish is often seen with semiaquatic forest dwellers. They have a distinct single vertebral keel that runs from the front till back of the carapax. This keel has a light yellow colouration. Often the colour of the keel is less distinct although still present with older Heosemys grandis. The carapax of the northern form is often very dark grey till black. These animals also have a darker bodycolor. The southern form has a dark brown base colour and lighter bodycolor. The plastron has a cream to yellow base colour and shows a black radiating pattern on each plate. Which fades and erodes so it is less distinct in adults.

Unlike seen with many other turtle and tortoise species the males are generally bigger than females. The carapax of the adult males has a very deep concavity to help with mating. Also the tail is longer and wider. With the cloaca placed further outside the plastron compared to females.

General behaviour:  Giant pond turtles, Giant temple turtles, Orange headed temple turtles,  Giant earth turtles or Wood turtles, whatever you want to call them, are a diurnal, semiaquatic turtle species. They can be found a lot in water as on land. As some of their common names suggest this is one of many species that are often kept in and around Buddhist temples. Where they can be found in relative high densities with other species of turtles.

Natural range and habitat:  In the book Terralog, Turtles of the world 4. By Holger Vetter and Peter Paul van Dijk they describe two forms. The northern form based in the lowlands of central Myanmar and the southern form that is based in their southern distribution including almost all of Malaysia, southern till central Thailand, almost all of Cambodia, only not in the eastern regions bordering Vietnam, the southern part of Vietnam and in Laos along the Mekong river delta. There seem to be some discussion on the possibility of Heosemys grandis also occurring in Singapore. But there is no evidence of a natural occurring population and the few animals that where found where mentioned to be introduced, escaped or originating from the food market. They are found in lowland habitats not higher than 400m above sea-level. They live in swamps, wetlands and seasonal forests. They are true semiaquatic animals and can be found hidden under leaflitter on the forest floor a lot. They live in cooler regions and are active from 12C till 24C. When temperatures rise above 26C they will hide  a lot in cooler microclimates between leaves, in burrows or in the water.

In their natural range they share their habitat with other turtles including the Cuora amboinensis sp, Siebenrockiella grassicollis, Cuora flavomarginata and Malayemys sp. Although the family Geoemydidae is known for its hybrids we have not found any documentation or pictures of hybrids with the Heosemys grandis.  

Captive requirements:  Hatchling and young Heosemys grandis spend most of their first years in shallow (temporary) pools or ponds in well vegetated areas. These shallow ponds are often warmer then the big ponds and full of all kinds of micro-fauna and amphibian larvae they can feed on. Young H. grandis can be raised in a simply decorated aqua-terrarium in shallow water measuring no more they their shell-length deep. Fill the water with roots, water plants and sphagnum for the young to rest on and get out of the water. With a stone slate of corkbark sheets a basking/land area can be created. In the first years H. grandis grows very fast and soon needs a bigger enclosure with a bigger landarea.

As adults these semiaquatic turtles need an enclosure that has a big land surface and a big pond. About a 30/70% till 40/60% land/water division. There turtles get big so they need a lot of space. A good measurement of thumb is that a pair needs an enclosure that is minimum 8 their shell long and 4x their shell wide. An adult pair of trio needs and watersection that is 250x120cm minimum plus a landarea of 100x120cm.  For each additional animal at least 30% more living space is added. H. grandis can be kept in groups and even together with other turtle species like Cuora amboinensis and Siebenrockiella grassicollis. As with any case of keeping animals together observe interaction between individuals. Males can not only be very aggressive towards other males and other turtle species during the mating season. They are also very persistent when it comes to their interaction and mating behaviour towards females. Stated is that Heosemys grandis males will not show a lot to any courtship but will roughly bite the female, try to pin her and mate. This can cause stress for the females when they are not willing to mate and it is best to separate these males and only introduce them in the mating season.

These turtles prefer shallow swamps and ponds where they mostly calmly walk across the bottom. So they do not need a deep pond, but they need to be able to fully submerge. Advisable is to provide the animals with a pond that is in the deepest part 1x till 1.5x their shell length deep. So for adults this is 40-60cm deep. Make sure the turtles can easily walk out of the pond or into shallow sections so it is advisable to build a pond that has a sloped bottom so the animals can easily walk into more shallow sections and out of the pond. Use a good filtration system do deal with the waste these turtles produce. Clean, oxygenated water prevents any health issues. Moving water is thereby advisable but prevent a very strong flow.

Use a good drainage layer under the land section to prevent any access water making the substrate to wet. Place on top a deep layer of substrate. You can use a mixture of sand, cocopeat and bark for this. Big piles of leaves are much appreciated to hide under and during the egg laying season females will look for these areas to lay eggs. Use big logs, cork bark, tubes and bamboo for decoration and to create visual barriers. This way animals can easily find a secure space to hide and also to separate themselves from any housemates. If there are not enough hides on the landarea the turtles will spend most of their time in the water.

Mist regularly to raise the humidity. Heating the pond will also help with this because of the evaporation. Heosemys grandis comes from seasonal forests and relative cool habitats. Average air-temperatures during the warmer months need to be around 24/25C with a maximum of 28C and heat the water till 25C. In captivity these big turtles will bask but often only for a short period. Still we advise to provide them with a moderate hotspot to thermoregulate and dry. A fluorescent tube with medium UVB output can be sufficient for their UVB requirements. Provide the animals with a light cycle of 13hours in the warm season and 11 hours in the cooler season.

Because these animals can tolerate cooler temperatures it is possible, when the temperatures allow this, to keep them in an outside enclosure. Always make sure that when you keep these animals in an outside enclosure there is plenty of possibilities to seek shading and hide from any direct sun.

Diet:  Heosemys grandis is a mainly herbivorous animal but will be opportunistic and in their natural range as well as in captivity they are observed feeding on carrion and other animal matter but they do not actively hunt on for instance fish. Suggested feeding ratio between meat/greens is for hatchlings and juveniles 40% animal matter, 25% greens and 25% fruit and 10% turtle/tortoise diet and some fungi as a treat. Adults need a 30% animal matter, 30% greens, 30% fruits and the other 10% eatable fungi, turtle/tortoise pellets etc. Their diet needs a relative low fat ratio and high nutritious value of minerals, vitamins and fibres. So make sure you don’t overfeed with animal matter or for instance the regular turtle pellets that are high in protein and fat.

Fed animal matter can be certain kinds of freshwater fish (if they accept it) like smelt, salmon and worms, snails, shrimp, mussel, crabs and crayfish, small mealworms and crickets for youngsters. Chicken(pieces) beef heart etc. Raw meat used for cats is also an option. These come in all kinds of fish variants and for instance with duck. With raw meat we mean the actual pure raw meat and bones mixtures in the freezer and not the canned foods that contain a low amount of pure meat and all kinds of extra ingredients that don’t do your turtle any good. Feed this on a flat dish on the land section to keep the water clean. The rest of the diet should consist out of all kinds of greens and seasonal fruits. Advisable greens included carrots, tomato, bell peppers, endive, pakchoi, white cabbage, all kinds of eatable fungi and mushrooms, nettle, brim, water hyacinth, hibiscus, banana leaves and fruit, spineless cacti, chicory, a low amount of cucumber, zucchini and all kinds of water plants. When you think about fruits do not only think of apples and pear but mostly of banana (including skin), figs, melon, peaches, grape, papaya, mango etc. Add Zoomed Tortoise diet to their list of edibles. Add a calcium supplement to two of the three feedings and a vitamin supplement to the other. Do not combine these supplements in a single feeding.

Young animals get fed almost daily while semi adults and adults get fed on average three times a week. Heosemys grandis is a calm moving animal that lives in often cooler regions so their digestive tract works not as fast as your average Chelonoides and this need to be taken into account to prevent your Heosemys will become obese which can cause several health issues.