The short answer is no. Dolphins (like all other mammals) aren’t cold-blooded.
Dolphins are marine mammals, and just like humans and other land-dwelling mammals, maintaining body heat is a significant component of a dolphin’s survival ability.
Dolphins, whales, and porpoises are all warm-blooded marine mammals.
Compared to marine mammals, fish and many amphibian species are cold-blooded and will adjust to match the temperature of their environment.
Cold-blooded animals do not require much body fat/blubber since their body adapts to varying climates and thus requires much fewer (heat-generating) calories to function.
Characteristics that are found among land-dwelling mammals and marine mammals include:
- Mammals are warm-blooded and have body fat or blubber to keep them warm
- Mammals have hair to better deal with cold wind and freezing environments
- Mammals give birth to babies (very few species produce eggs). Note: Most mammals give birth to a single offspring.
- Mammals breathe air (they are unable to extract oxygen from the water like fish and amphibians)
- Mammals produce milk to feed their babies (nurture is often an essential factor in a young developing mammals life)
Characteristics that are found among fish and amphibians include:
- Fish and amphibians are often cold-blooded and can adjust to the temperature in their environment without needing body fat or blubber to stay warm.
- Fish and amphibians are not known to possess hair. Instead, they may have moist skin, scales, or an exoskeleton.
- Fish and amphibians typically lay eggs; some produce thousands of eggs yearly.
- Being able to extract oxygen directly from the water through the use of gills or specialized organs
- Fish and amphibians aren’t known to provide much nurture to their children, and many species are left to hunt and fend for themselves as soon as they are born.
For dolphins to maintain their body heat in cold climates, they have developed a thick layer of insulating fat which helps protect their vital organs from the cold oceanic waters.
The thickness of the dolphin’s blubber is only a critical factor in keeping a dolphin warm.
The blubber’s lipid concentration is equally important in maintaining body heat.
Dolphins with a high lipid concentration but a thin layer of fat may be better equipped to stay warm than a dolphin with a thicker layer of blubber but a lower lipid concentration.
Simply put, having a higher lipid concentration equals better insulation from the cold.
Another exciting feature that helps prevent dolphins from freezing is their body’s ability to increase its metabolic rate, which increases the number of calories the dolphin burns allowing it to produce and transfer heat throughout their blood, vital organs, and muscles when in frigid environments.
Most warm-blooded mammals require significant amounts of calories to maintain their body heat and keep themselves healthy, as their metabolism requires large amounts of energy to function correctly.
Also, just like a human, when a dolphin is in a cold environment, its muscles may cause involuntary shivering.
It helps keep the dolphin warm by burning calories, creating friction, and producing heat.