Why whales don’t get brain damage when they swim

Special blood vessels may protect whales from pulses in their blood that would damage the brain while swimming, new research has suggested.

Whaley high blood pressure

Land mammals such as horses experience ‘pulses’ in their blood when galloping, where blood pressures inside the body go up and down on every stride. UBC researchers have suggested for the first time that the same phenomenon occurs in whales when they swim.

Bated breath

Locomotion can forcefully move blood, causing spikes in pressure. The difference in pressure between the blood entering and exiting the brain for these pulses can cause long-term damage. Horses deal with the pulses by breathing in and out, but whales hold their breath when diving and swimming.

Wonderful nets

The research team, led by UBC zoologists Drs. Margo Lillie and Robert Shadwick theorized that special networks of blood vessels cradling a whale’s brain and spine, known as ‘retia mirabilia’, use a ‘pulse-transfer’ mechanism to ensure there is no difference in blood pressure in the cetacean’s brain during movement. The team developed a computer model which predicted these retia can indeed deal with 97 per cent of a pulse, backing their theory up.

Interview language(s): English (Shadwick, Vogl)