Cortisol is a hormone that helps humans and many other animals regulate their energy use and respond to changing conditions. For a long time, sharks and rays were believed to rely on a different steroid hormone for these functions, without producing cortisol themselves. Now, a new study of Nort...

Source: [Phys.org](https://phys.org/news/2026-10-spiny-dogfish-blood-hormone-thought.html)

Sponsored