How do dolphins stay warm in cold water?

Blubber: Dolphins, like other marine mammals, have a thick layer of blubber that helps to insulate their bodies and maintain their body temperature. Blubber is a layer of fat that lies under the skin and helps to reduce heat loss.

Counter-current heat exchange: Dolphins also have a specialized cardiovascular system that helps them to conserve heat. This system involves a network of blood vessels that lie close together and exchange heat as the blood flows through them. As warm blood flows from the body's core to the extremities, it transfers heat to the cooler blood returning from the extremities. This helps to keep the body's core temperature from dropping too low.

Active swimming: Dolphins are active swimmers and their muscles generate heat as they move. This heat helps to keep their bodies warm.

Large body size: Dolphins have relatively large body sizes, which also helps them to stay warm. Larger animals have a lower surface-area-to-volume ratio, which means they lose less heat per unit of body mass.

Behavioral adaptations: Dolphins may also engage in certain behaviors to help stay warm. For example, they may huddle together in groups to reduce heat loss or they may seek out warm water currents.