If a human falls in the cold sea, he might die of hypothermia in minutes. Even people with plenty of body fat may not last long.

 

Like humans, dolphins are warm-blooded mammals but they don’t have any hair to keep them warm. How do dolphins keep warm in the cold sea?

 

Even though dolphins don’t have a fur coat to keep them warm, they are able to stay warm in the cold sea.

 

Dolphins have a layer of blubber under their skin which keeps them warm. They also have less of their body mass exposed to the outside which means they cool more slowly. 

 

Not only that, but, dolphins are able pump out 'metabolic' or body heat more quickly than animals like humans. 

 

Dolphins can also change the flow of blood so that not so much blood goes to their outer parts like tail flukes and pectoral fins.

 

Equally, when they're feeling hot, dolphins don't sweat like humans, but can pump blood to their outer-parts to cool more quickly.

 

Source: Dudzinski