No, whales are not cold-blooded animals.
Like most marine mammals and land mammals whales are warm-blooded creatures.
Most fish and many amphibious species on the other hand are cold-blooded animals.
Whales belong to the family known as Cetacea and make up one of three groups within the cetacean species; the other two are dolphins and porpoises.
As a whole there are currently around 80 – 90 recorded species of cetacea so far.
All cetaceans are marine mammals and share several characteristics with most land mammals including:
- Being warm-blooded
- Having hair (some whales have hair at birth that falls of shortly after)
- Giving birth
- Breathing air (whales get their oxygen above the surface of the water)
- Producing milk (to feed their young)
Most fish and amphibians share several characteristics that are common among their species such as:
- Being cold-blooded or ectothermic (most species are cold-blooded/ectothermic and do not need fat to maintain their body heat)
- Lay eggs (most species lay eggs externally, but a few hold their eggs internally)
- Breathe through specialized gills, organs or skin (some amphibians and all fish can breathe underwater)
While fish and amphibians are able to live in various climates without blubber or body fat this is not the case for cetaceans.
In order for whales to keep warm in cold/polar climates whales have developed a thick layer of insulated blubber, which protects against freezing winds and water.
Depending on the species the thickness of their blubber can vary anywhere from 2 inches to over 1 ft in thickness.
In some species this layer of blubber can even account for up to 50% of the marine mammals total mass during certain periods of its life (most likely during heavy feeding seasons).
Surprisingly the thickness of the whales blubber doesn’t fully account for a whales ability to stay warm in cold environments.
The lipid and water concentration in the whales blubber plays a large role in maintaining the whales body heat.
The higher the lipid concentration the warmer the whale is and vice versa.
In other words whales that have less blubber but a higher lipid concentration may actually be able to maintain their body heat better than a whale with low lipid levels and a higher level of blubber.
This becomes extremely important during mating season as some whale species make long migration trips towards the equator.
While on this trip some whales will completely forgo eating for several months where they live almost completely off of their fat/blubber stores that they gained during their feeding season.
During this time whales can lose significant amounts of blubber by converting it into energy while on their long migration.
In addition to providing whales with energy reducing their blubber also helps these marine mammals deal with the hotter climates near the equator where they mate.
Once they reach their mating grounds these whales will then begin courting females, mating and bearing offspring for several months.
When feeding season comes back around these whales will travel back towards their feeding grounds to restore lost energy/blubber, and prepare for the next mating season.
In addition to having a thick layer of blubber whales are also known to consume large amounts of calories, which is common among warm-blooded animals.
Eating lot’s of calories is often necessary to keep the body warm and the metabolism working effectively.
In fact whales can consume anywhere from 2% – 10% of their body weight in food on a daily basis.
An adult blue whale for example can consume as many as 40 million krill or 8,000 lbs. of krill on a daily basis in order to power its massive body.
As stated earlier many species of fish and amphibians are cold-blooded so they can survive off of fewer calories due to the fact that they do not need to keep their body fueled with heat or add layers of fat/blubber to keep them warm.
Note: By stocking up on large quantities of food during feeding periods whales can develop a sufficient amount of energy to allow them to survive without eating while on their migration trips.