How marine currents influenced the widespread natural overseas dispersal of reptiles in the Western Indian Ocean region

Natural overseas dispersal, not human translocation, was the primary driver for the widespread colonization of terrestrial reptiles, including giant tortoises, across the Western Indian Ocean (WIO) region. A review of recent literature reveals that nearly 90% of successful reptile colonization events align with prevailing marine surface currents, which can facilitate long-distance dispersal despite geological and evolutionary time scales. The study also highlights the role of eddies and counter-currents in enabling transport against main current directions. By analyzing extant and extinct WIO giant tortoise lineages, researchers demonstrate that their current distribution patterns are consistent with natural dispersal mechanisms, challenging earlier hypotheses involving human intervention.

Hawlitschek, O., Ramírez Garrido, S., & Glaw, F. (2016). How marine currents influenced the widespread natural overseas dispersal of reptiles in the Western Indian Ocean region. Journal of Biogeography, 44(6), 1435–1440. Portico. https://doi.org/10.1111/jbi.12940