Dolphins and tuna can swim so fast

Dolphins and tuna can swim so fast that the water around their tails cavitates.

When the bubbles [formed by cavitation] collapse, they produce a shockwave, which eats away the metal in propellers. To dolphins, it is painful. According to the researchers’ calculations, within the top few metres of the water column, this happens when the dolphins reach 10 to 15 metres per second (36 to 54 kilometres per hour).

Tuna don’t have this pain problem; their tails don’t have nerve endings.

• dolphins
• science