Butter is a thick layer of fatty tissue that lies between the muscles and skin of marine mammals. It serves as a source of energy for these animals during lean periods, and also insulates them from extreme cold. In particular, arctic animals tend to have dense deposits of this tissue, as they live in an extremely cold environment. Humans have also found a variety of uses for fat, ranging from an essential part of the Arctic diet to a form of fuel.
Whales, seals and polar bears, among others, are fat. The material covers the torso, it does not extend to the appendages like the fins. It occurs at different depths around the body, depending on the type of animal and the conditions in which it lives, and can sometimes represent up to 50% of an animal’s body weight. When marine mammals have difficulty finding food, they use these tanks as energy, filling them when food is most abundant.
The structure of fat is slightly different from that of other types of fatty tissue. Bacon is a highly vascularized fat, meaning it is full of a variety of blood vessels. Its thickness allows it to act as a thermal insulator for animals while keeping the animal’s blood warm. Unlike skin, fat is not compressed under pressure, so it will retain heat more effectively than a thick layer of skin.
Like other fatty tissues, fat makes animals more floating, a useful trait for marine mammals. Because these animals spend much of their lives in water, fat is very important for their overall health. If an animal’s stock is severely depleted, the animal will not be able to survive as it will lack energy, thermal insulation and natural buoyancy. This is a major concern for animals such as polar bears that cause severe depletion of habitat, reducing available food sources, causing animals to metabolize their fat.
Historically, humans in the Arctic have also relied on fat. It has served as a food source for many people in the north of the world and has also been burned as fuel to heat and light homes. The fat of marine mammals is removed in long strips that are plucked with fat knives and then melted into large pots. The rendering process is quite dirty and smelly, which makes many appreciate that this substance is no longer a major source of food and fuel.