Phylogenetic analysis suggests fully aquatic mammals are unlikely to evolve back into terrestrial creatures

A trio of biologists and environmental scientists, two with the University of Fribourg and the third with the Swiss Institute of Bioinformatics, has found that fully aquatic mammals, such as whales and porpoises, are very unlikely to evolve back into land animals. In their study, reported in Proceedings of the Royal Society B, B. M. Farina, S. Faurby and D. Silvestro conducted phylogenetic analyses of more than 5,000 mammalian species.