Hippopotamus evolved on the continent of Africa twenty million years ago.these animal can not swim and even it can not float.but bone fossil of pygmy weighed about 400 kg found on the Madagascar island which is located 400 km east of the African continent.
it should be noted that both the African continent ans the Madagascar island is separated by two km depth of sea.therefore the question araised as to how these animal able to reach the island?
similarly the presence of lemur monkeys on the island of Madagascar which is also evolved on the main land of African continent has also been a riddle for a long time.
but many researchers believed that the ancestor of lemur monkeys may have reached the island on floating plant material.
but the bone fossils of the extinct Madagascar dwarf hippopotamus has been estimated to be 400 kg.
therefore the dwarf hippopotamus can not float on floating plant debris.
therefore the presence of dwarf hippopotamus on the island of Madagascar proved ancient land connection between the Africa and the Madagascar island due to two km of low sea level.