Did you know that the flippers of cetaceans have great similarities with the bone structure of human hands?  

As cetaceans evolved from terrestrial mammals with weight-bearing forelimbs to an aquatic world, their forelimbs turned into a flipper that is constructed of soft tissue. Having elongated and streamlined flippers in an aquatic environment helps with lift, breaking, turning and stabilising the animal while swimming.  

In addition to soft tissue development, the bone morphology of most cetaceans changed to better support the changing flipper shape. Like most baleen whales, humpback whales for example only possess four digits, with their second digit Did you know that the flippers of cetaceans have great similarities with the bone structure of human hands?  

As cetaceans evolved from terrestrial mammals with weight-bearing forelimbs to an aquatic world, their forelimbs turned into a flipper that is constructed of soft tissue. Having elongated and streamlined flippers in an aquatic environment helps with lift, breaking, turning and stabilising the animal while swimming.  

In addition to soft tissue development, the bone morphology of most cetaceans changed to better support the changing flipper shape. Like most baleen whales, humpback whales for example only possess four digits, with their second digit being largely elongated. In contrast, toothed whales like killer whales, have five digits. Researchers are not in agreement what exactly causes the digit reduction, but hypotheses assume that narrow and longer flippers for most baleen whales could be associated with remaining stable when swimming at higher speeds for lunge feeding, while more broad flippers may offer a larger surface area for manoeuvring tight turns at lower speed and shallower lagoons.  

Read the full study on the ‘Evolution of hyperphalangy and digit reduction in the cetacean manus’ by Cooper et al. (2007) here: https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.20532 

To learn more about cetaceans in NAMMCO’s management area, follow this link: https://nammco.no/whales-dolphins-and-porpoises/