Whales, seals and dolphins followed a similar evolutionary path from land to sea

By Brooks Hays

May 22 (UPI) -- New research shows whales, seals and dolphins followed similar evolutionary patterns during their journey from land to sea.

By retracing the evolutionary paths of predatory marine mammals, researchers hope to better understand the importance of whale, seal and dolphin species to vulnerable marine ecosystems.


All marine mammals share common land-dwelling ancestors. But how did these early relatives make the transition back into the waters?

Researchers at Monash University in Melbourne, Australia, set out to trace the morphological and behavioural adaptations that allowed land-dwellers to return to the sea as underwater predators.

Their efforts revealed similar sequences of adaptations for each marine mammal lineage.

Researchers divided the pattern of adaptations into three distinct paths followed by three different types of feeders: raptorial feeders, suction feeders, and filter feeders. Raptorial feeders use their jaws and teeth to capture and consume prey. Suction feeders vacuum small prey into their mouths. Filter feeders, such as today's largest whale species, use hair-like strands to strain krill from the ocean currents.

Researchers divided each of the three adaptational paths into sections to reveal similar large-scale patterns. Each type of feeder progressed through a sequence of adaptions to: first, capture prey; second, manipulate and process prey; third, remove water; and finally, swallow prey.


Though different lineages adopt different behavioral adaptations for each feeding strategy, the pattern remains the same. Previous research has shown flying species from different lineages -- including birds, pterosaurs and bats -- also followed similar patterns of adaption.

Researchers detailed their analysis in the journal Proceedings of the Royal Society B: Biological Sciences.

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