Diving marine mammals take deep prey plunges to heart
![Weddell seal](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/01/WeddellSealEdit_0.jpg?fit=840%2C470&ssl=1)
Diving can put a lot of stress on the heart. Even animals evolved for diving, like Weddell seals, develop irregular heartbeats when they take a deep plunge.
Natalie Tapson / Flickr (CC BY-NC-SA 2.0)