A recent study has found that most of present-day fauna of Madagascar, the world’s fourth largest island, may originally have arrived across long distances by air or sea. The island of Madagascar is home to many unique vertebrate species, but how, when, and from where Madagascar’s vertebrates arrived on the island is a poorly understood mystery.
A group of international researchers now reveal that it is most likely that those vertebrate-arrivals swum, rafted or flew the long distance across the ocean. The researchers analysed data (arrival date, source, and ancestor type) on vertebrate arrival patterns of currently existing taxonomic groups.
The study suggests that species that relied on swimming (like crocodiles) or rafting, using land masses as rafts, and exclusively coming from Africa’s mainland, were most successful when winds and ocean currents worked in their favour. As soon as the ocean currents shifted, flying species such as bats became the main immigrants. “These findings are a step toward explaining the uniqueness of the fauna and the current species diversity of the world’s fourth largest island,” according Karen Samonds, one of the authors.
(Sources: PNAS, 19.03.2012; ScienceAlert, 21.03.2012)
