plants, and will occasionally eat carrion. In captivity, however, they should never be fed meat. The sexual dimorphism of adult Indian star tortoises is quite apparent. Females are considerably larger than their male counterparts. In addition, the females' plastrons are much flatter than those of the males, which have a concave shape. The shape of this creature is presumed to be specially adapted to naturally assist it to return to a stable stance after it has been turned over. Mathematicians Gábor Domokos of the Budapest University of Technology and Economics and Péter Várkonyi of Princeton University designed a homogeneous object called a gömböc that has exactly one unstable balance point and exactly one stable balance point. Just as a bottom-weighted (nonhomogeneous weight distribution) sphere would always return to the same upright position, they found it was possible to construct a shape that behaves the same way. After that, they noted the similarity to the Indian star tortoise and subsequently tested 30 turtles by turning them upside down. They found many of them to be self-righting. Distribution and habitat The Indian star tortoise ranges from India (except Lower Bengal), extending west to Sindh province (Pakistan) and Sri Lanka. A large number of specimens of this species are found in the illegal wildlife trade in India. Few studies exist which have quantified wild populations and the effect of trade on them. References External links Indian Star Tortoise Geochelone Reptiles of South Asia Reptiles of Pakistan Reptiles of India Reptiles described in 1795 Reptiles of Sri Lanka Species endangered by the pet trade Species endangered by agricultural development Taxa named by Johann David Schoepff Reptiles as pets