One question that frequently gets asked about dolphins, especially those that live in cold water environments is, how do dolphins stay warm?
Since dolphins aren’t born with hair and they live in oceanic environments that are several times as thermodynamically cold conducting as air it is important to understand how dolphins are able to deal with cold waters when other mammals such as humans are much less capable of surviving in the freezing ocean.
Note: There are actually some species that are born with hair, but the hair falls off shortly after birth.
Dolphins are marine mammals and like almost all mammals they are warm-blooded animals which means they must maintain a certain level of body heat in order to survive, maintain their energy and keep their vital organs functioning properly.
To assist dolphins in staying warm they have certain internal metabolic processes that help them turn food into energy which increases their body’s ability to produce heat and helps stabilize their bodies temperature in cold environments.
By increasing their metabolic rate the dolphins body burns more calories and transfers heat through their blood to vital organs and muscles.
In addition to this dolphins are able to shut down non-essential organs in order to focus their energy on the areas that need the most heat.
When a dolphin does get cold their muscles may begin to shiver just like a humans does.
By shivering the muscles create additional energy and heat allowing the dolphin to stay warm when it is in very cold environments and prevents the muscles from stiffening up.
One of the most well-known ways for dolphins to stay warm has to do with the fact that dolphins have a thick layer of insulated blubber that surrounds their body.
Depending on the species of dolphin the thickness of a dolphins blubber can vary considerably.
If you include all cetacean species such as the great whales then the amount of blubber these marine mammals may have can vary from 2 inches to over 1 ft. thick.
Interestingly the thickness of the dolphins blubber may not be the only important factor in keeping the dolphin warm as their lipid concentration can play an equally important role in maintaining body heat.
In fact dolphins that have a thin layer of blubber but a large amount of lipids in their blubber may actually do a better job of staying warm in the cold than dolphins that have a thick layer of blubber but a low concentration of lipids.
To make it easier to understand higher lipid concentration equals better insulation.
You can think of it as wearing leather or well constructed wool when you’re in the cold as compared to breathable cotton or non insulated clothing.
This can help explain why some dolphin species are able to survive in extremely cold climates despite their small size.
For dolphins that are larger in size (such as the killer whale) their large body allows them to better displace heat throughout their body while keeping their internal organs warm.
This can be thought of as comparing one humans body fat to another.
In many cases a person with more body fat is able to stay warmer than a thinner individual in the same climate due to the displacement of heat being producing by their larger body.
In addition to providing dolphins with a way to stay warm in cold climates blubber can also provide dolphins with additional fat which they can use to burn for energy when they have difficulty finding food and have to go for extended periods without eating.