Why Do Seals Have Blubber?

Blubber lies just under a seal’s skin and covers most of its body. Blubber contains blood vessels, which help keep the seal warm. When the seal enters cold water, its blood vessels react by slowly becoming narrower. This process decreases the amount of blood that flows through the layer of blubber. With blood flow reduced, the seal doesn’t need to produce as much energy to stay warm. Blubber isn’t only valuable to seals; people in some parts of the world hunt seals and eat their blubber and skin.

Seals, like other mammals, need to maintain a consistent body temperature, which can be difficult when exposed to changing water temperatures. The Cetacean Watching website notes that temperature control can be challenging because heat loss occurs 25 times faster in the water than in the air. Without the extra insulation of a layer of blubber under their skin, seals would lose heat faster than their bodies could produce it and would be in danger of dying in frigid water.

Seals carry their own emergency food source with them. Food can be scarce during cold winters, but a nice, thick layer of blubber helps keep seals alive. A seal’s body draws on the energy stored in its blubber to help it survive during lean times or during fasting periods. Blubber provides seals with all the nutrients they need to survive, including fats and proteins. Female seals build up thick stores of blubber during pregnancy. After the babies are born, the mothers use the blubber stores for energy while they nurse their young.

Blubber helps seals swim through water more efficiently. The long, narrow shape of a seal’s body helps it move easily through the water, but blubber also plays an important part in a seal’s swimming ability. The thick layer of fat acts as a natural flotation device and helps the seal maintain its buoyancy in the water. Without blubber, a seal would be unable to rest in the water and would sink if it became too tired to swim.