If only for reasons of terrestrial mobility, you probably shouldn't populate your whole superhero squad with cetaceans. Evil lairs on land would be difficult for you to infiltrate, to say the least. But you'd do well to consider including a dolphin or two in your next hero league. Dolphins were all over science journals last week, displaying powers that could put certain superheroes out of business.
WolverineA letter published in Nature's Journal of Investigative Dermatology pointed out that bottle-nosed dolphins have remarkable healing abilities. They have plenty of run-ins with sharks: one survey found that 40% of dolphins had visible shark-bite scars. But all of these wounds had healed without killing the dolphins from blood loss or infection.
The author, Michael Zasloff, also cites observations of dolphins healing in captivity. Despite having wounds a foot long and more than an inch deep--reaching all the way through their skin and blubber--these dolphins were as good as new just four weeks later. What's more, they showed no signs of pain while they went about their business.