A new study published in *Proceedings of the Royal Society B* suggests that whales and dolphins are evolutionarily locked into their aquatic lifestyle. Researchers, including Bruna Farina from the University of Fribourg, analyzed the morphological and genetic changes these cetaceans underwent during their transition to aquatic life. The study emphasizes Dollo's Law, which states that complex evolutionary changes, such as limb reduction and the development of echolocation, are virtually irreversible.
The research highlights that while some marine species initially ventured onto land, dolphins and whales adapted to a fully aquatic existence. This transition involved significant adaptations like increased body size and modified limbs. Although cetaceans retain some ancestral traits from their land-dwelling ancestors, the genetic and morphological changes they've undergone make a return to terrestrial life impossible, leaving them vulnerable due to their dependence on a single habitat.