Sea mammal breath-holding explained
13 June 2013 Last updated at 21:23 BST
Scientists say they have solved the mystery of one of the most extreme adaptations in the animal kingdom: how marine mammals store enough oxygen to hold their breath for up to an hour.
The team studied myoglobin, an oxygen-storing protein in mammals' muscles and found that, in whales and seals, it has special "non-stick" properties.
This allowed the animals to pack huge amounts of oxygen into their muscles without "clogging them up".
The findings are published in Science.
Here, Dr Michael Berenbrink from the Institute of Integrative Biology at the University of Liverpool, visits the seal cove at Blue Reef Aquarium in Tynemouth to explain his team's discovery.