Species Spotlight: Asian Giant Tortoise

Manouria-emys-asian-forest-tortoise.jpg

OVERVIEW

Common name:  Asian Giant Tortoise

Scientific name:  Manouria emys

Range:  Bangladesh; India; Indonesia; Malaysia; Myanmar; Thailand; Singapore (extinct)

Conservation status: Critically Endangered on the IUCN Red List, currently protected under CITES Appendix II. 

INFORMATION

The Asian Giant Tortoise is native to South Asia, in particular, the countries Bangladesh, India, Indonesia, Malaysia, Myanmar and Thailand (Choudhury et al., 2019). The Asian Giant Tortoise exclusively inhabits evergreen forest, including bamboo forest, dry evergreen forest mixed with bamboo, dry evergreen forest, stream courses and swampy stream edges (Wanchai, 2007), from lowland regions up to altitudes between 600 to 1,500 meters (Choudhury et al., 2019). This species is typically found near water, particularly streams, and burrowing in damp soil (Nutphand, 1979), except during the raining season, at which time they can be found foraging at greater elevations (Wanchai, 2007). 

The Asian Giant Tortoise is a highly social species that exhibits complex social behaviour with elaborate dominance and courtship rituals, and communicates through a variety of vocalization, and head and neck movements (McKeown et al., 1990). The Asian Giant Tortoise is the largest land tortoise in mainland Asia, and is comprised of two subspecies: Manouria emys phayrei and Manouria emys emys (McKeown et al., 1990). The former is generally darker in color with a dark brown, olive or black domed upper shell that can grow up to 60cm in length and 37kg, in contrast to the latter, who is characterized by a flattened, lighter yellowish brown upper shell that can reach 50cm in length and 20kg (Nutphand 1979; Kundu et al., 2018). 

THREATS AND CONSERVATION

Asian Giant Tortoises are traded internationally for the primary purpose of consumption in East Asia for meat and for use in traditional Chinese medicine (Choudhury et al., 2019). Wild-caught animals are also traded internationally in the global pet trade, where they command a high price: $500 and $650 USD and M. e. phayrei and between $1,300 and $1,575 USD in 2007 (Stanford et al., 2015). Moreover, as the species becomes rarer in the wild due to over-exploitation, their value in the market increases, and they become more desirable for poachers in the illegal trade market. 

The threat of over exploitation of this species for international trade compounds the threat it faces from declining area, quality and extent of its suitable habitat. The quality and area of habitats occupied by the Asian Giant Tortoise are rapidly declining, with half of suitable lowland and mid-elevation evergreen forests having been degraded and lost over the past fifty years due to logging, agriculture, forest fires, and hydroelectric dams and reservoirs and associated infrastructure (Choudhury et al., 2019). Because of its long-term exploitation, the severe destruction of its natural habitat and resulting decline in its populations, any international trade, legal or illegal, has a detrimental impact on the survival of this species in the wild.  

REFERENCES

  1. Choudhury, B.C., Cota, M., McCormack, T., Platt, K., Das, I., Ahmed, M.F., Timmins, R.J., Rahman, S. & Singh, S. 2019. Manouria emys (errata version published in 2019). The IUCN Red List of Threatened Species 2019: e.T12774A152052098.

  2. Wanchai, P., 2007. Radio-telemetry study of home range size and activities of the black Asian giant tortoise Manouria emys phayrei (Blyth, 1853) (Doctoral dissertation, Chulalongkorn University).

  3. Nutaphand, W., 1979. The turtles of Thailand. Siam Farm Zoological Garden.

  4. McKeown, S., Meier, D.E. and Juvik, J.O., 1991. The management and breeding of the Asian forest tortoise (Manouria emys) in captivity. In Proceedings of the First International Symposium on Turtles & Tortoises: conservation and captive husbandry (KR Beaman, F. Caporaso, S. McKeown, and MD Graff, editors). Chapman University and California Turtle and Tortoise Club, Orange and Van Nuys (pp. 138-159).

  5. Kundu, S., Kumar, V., Laskar, B.A., Tyagi, K. and Chandra, K., 2018. Morphology and genetic variation in the endangered tortoise Manouria emys: distinct lineages or plastron anomalies?. Mitochondrial DNA Part B, 3(1), pp.166-170.

  6. Stanford, C.B., Wanchai, P., Schaffer, C., Schaffer, R. and Thirakhupt, K., 2015. Manouria emys (Schlegel and Müller 1840)—Asian giant tortoise, giant Asian forest tortoise. Conservation biology of freshwater turtles and tortoises: a compilation project of the IUCN/SSC tortoise and freshwater turtle specialist group, Chelonian research monographs, 5(8), p.086.


Species SpotlightLindsey Zehel