How long can a whale hold its breathe?

Sperm whales make some of the longest dives achieved by mammals, with some lasting up to 90 minutes! While dolphins and other whales can stay underwater for 20 minutes.

Scientists know it has something to do with their myoglobin (a molecule in the blood that helps the body's muscles retain oxygen). 

In creatures like cows and humans, myoglobin is known for giving flesh its reddish tinge; seals and whales, on the other hand, have extremely high myoglobin concentrations that make their tissue look black. 

The trick, apparently, is that the myoglobin of marine animals is positively charged, like one end of a magnet. Instead of clumping together, the molecules repel each other, ensuring the blood stays loose and lubricated. 

The whale's ability to hold its breath is, in a way, an evolutionary one-two punch: 

  1. The high concentration of myoglobin allows it to spend more time underwater in between breath
  2. The myoglobin's positive charge ensures the proteins don't clump together and kill the animal.