Why are some fish warm-blooded? Predatory sharks gain speed advantage, study finds

New research from marine biologists offers answers to a fundamental puzzle that had until now remained unsolved: why are some fish warm-blooded when most are not? It turns out that while (warm-blooded) fish able to regulate their own body temperatures can swim faster, they do not live in waters spanning a broader range of temperatures.

source https://www.sciencedaily.com/releases/2021/07/210701112702.htm