Family : TESTUDINIDAE
Species : Manouria impressa
Maximum carapace length : 31 cm

The Impressed Tortoise Manouria impressa is one of just 4 species of native land tortoise occurring in Southeast Asia. This is the smaller of two species of the genus Manouria, the other being the larger Asian Giant Tortoise Manouria emys.

In evolutionary terms, tortoises of the genus Manouria are considered to show primitive characteristics.

The Impressed Tortoise inhabits humid, moist hill and montane forest up to elevations of at least 1300 metres, though the precise altitudinal range appears confused in the literature.

This is considered to be a rare species, which is threatened by poaching for traditional medicine and for the pet trade, even though they are notoriously difficult to keep alive in captivity.

The curious name of this species refers not to its expression or demeanour, rather to the concave nature of the scutes (i.e. the scales) which comprise its markedly flat carapace. The marginal scutes at the rear of the animal are serrated, and in some specimens the three frontal scutes above the head and neck (the middle of which is the nuchal scute) are elongated, which provides additional protection to the top of the head.

The carapace is orange-brown to dark brown in colour, and individual scutes typically have darker margins.

The front limbs are adorned with stiff, elongate scales. The head is yellow to cream, with pink markings : male specimens reportedly have darker heads.

The species has been well documented feeding on mushrooms, which appear to comprise the bulk of its diet. Other dietary ingredients might include grasses such as bamboo.

A study of the species in Phu Luang Wildlife Sanctuary, Thailand (Wanchai et al, 2012) showed a small home range of no greater than 17.7 hectares, and generally considerably less. Thus, these tortoises appear to live in very localised areas of forest.

Females are larger than males, and they lay around 20 or so eggs in a shallow scrape, which is then covered with a mound of leaf litter and some loose soil (see Fig. 8). The female will defend this nesting site as far as possible from predators such as monitor lizards.

This rarely encountered tortoise occurs in parts of eastern Myanmar, Thailand, Laos, Cambodia, Vietnam and northern Peninsular Malaysia.

Figs 1 and 2 : Specimen from 1300 metres elevation in lower montane forest of the Titiwangsa Mountains (the 'Main Range') of Peninsular Malaysia. This is believed to be a male, based on the dark markings on the side and top of the head. The straight carapace length measured an estimated 25 cm.

Fig 3 : Top view of the head of the same specimen showing the elongated scutes at the front of the carapace.

Fig 4 : Close-up of the elongated, pointed scales and claws of the front leg and foot.

Figs 5 and 6 : A confirmed female specimen from the same area of the Titiwangsa Mountains, found guarding a nesting mound. Note the absence of dark markings on the head.

Fig 7 : Rear view of a female showing posterior marginal scutes, which are serrated, and spurs either side of the tail. Photo thanks to Leong Tzi Ming.

Fig 8 : A nest being excavated by a Crab-eating Mongoose Herpestes urva, which is probably searching for eggs to consume.

Thanks to David Gray and Dogforce for locating two of these specimens in thick forest, and for sharing observations. 


References : H1, H12

Wanchai, P., Stanford C.B., Thirakhupt, K., Thanhikorn, S.  2012. Home Range of the Impressed Tortoise, Manouria impressa (Günther, 1882) at Phu Luang Wildlife Sanctuary, Loei Province, Thailand. Tropical Natural History 12 (2): 165-174