Yes, whales are mammals, however due to the fact that they live in the ocean these large animals are referred to as marine mammals.
In fact the blue whale is the largest living mammal (and animal species) on this earth.
In terms of size the blue whale can grow to lengths of over 90 ft. long and weigh more than 150 tons.
Just like land mammals whales possess a number of characteristics that are necessities among the many different mammalian species.
Some of these factors include:
- Breathing air – Mammals have lungs and require air to breathe, so they are unable to breathe underwater like fish and amphibians
- Producing milk – Mammals nurse their young and feed them nutrient/fat rich milk during their early stages of life until they are able to consume solid foods on their own.
- Being warm-blooded – Mammals are warm-blooded animals that receive their energy by consuming food on a regular basis. In order to protect themselves from the cold most mammals develop a layer of fat, blubber and/or hair which provides them with additional calories during food shortages and helps keep their vital organs from freezing.
- Giving birth – Mammals carry their young internally and provide their child with nutrients through an umbilical cord until the child is born. Most non mammalian species lay eggs rather than giving birth.
As a whole there are currently over 5,000 known mammal species alive today.
Why are whales mammals?
Believe it or not the earliest known ancestors of whales were land mammals.
Over the course of millions of years whales have slowly evolved from living on land to inhibiting the ocean, which helps explain why whales are warm-blooded, give birth to their and require air in order to survive rather than being born with qualities similar to fish and amphibians.
In fact whales still carry signs of their land dwelling past in their bone structure.
The bones in a whales fins for instance indicate the existence of limbs that were believed to have once been used for hunting, survival and traveling on land rather than swimming in the water.
A close examination of the bones in their fins appear to show individual digits which may have helped their ancestors walk, grab objects and fight.
The same mammalian design can also be seen in the whales back.
The vertical movement of their spine indicates a body that was more likely used for running on land rather than swimming in the ocean.
This is a direct comparisons to the bone structure of a fish, which historically appears to have been developed for primarily for swimming.
When observing the differences in swimming styles between whales and fish this point is further illustrated.
When a whale swims in the water it propels itself by arching its back up and down while using its flukes to move forward.
Fish and sharks on the other hand move from left to right in order to travel through the water.
In addition to whales there are also a number of other animals that are considered marine mammals.
These animals include:
When it comes to the cetacean family whales, dolphins and porpoises are considered part of this grouping as they share many of the same physiological and evolutionary traits with one another.
The cetacean family excludes marine mammals such as seals and walruses.
Just to recap both land mammals and marine mammals share a number of characteristics that are required to be considered a mammal.
Some of these characteristics include:
- Being born a warm-blooded animal
- Nursing their offspring with milk
- Carrying children in the womb (mammals have a gestation or pregnancy period that can vary among different species)
- Possessing lungs (mammals breathe air through their lungs rather than having gills)
- Possessing body hair (not all animals possess body hair and some animals such as whales may lose their body hair shortly after birth.
How are fish different from whales?
Despite the fact that they are both animals and share the ocean together their are many distinct differences between aquatic animals like fish and marine mammals such as whales.
For starters fish have gills that allow them to pull oxygen through the water using a gas exchange method.
In order to extract oxygen fish pull water into their mouth and run the water over their gills in order to extract the oxygen from the water.
The oxygen is then distributed through the fishes bloodstream to its vital organs.
Depending on the species the blood may flow in a counter-current direction in order to maximize the use of oxygen.
Another large difference between fish and mammals is the fact that fish produce eggs rather than carrying their young in a womb.
For aquatic animals such as fish this is an important part of their survival as fish are able to lay hundreds or thousands of eggs in a signal year and since marine mammals such as whales can consume large quantities of fish on a daily basis the fish need to be able to produce enough offspring in order to continue thriving in the ocean.
If fish were to give birth to their offspring and carry their children internally they would not be able to produce nearly enough offspring to pass on their genes.
While there are many factors that differentiate fish from marine mammals we’ll give you one more example of the distinct differences between these two types of animals.
Unlike whales fish are mostly cold-blooded animals.
Being cold-blooded allows fish to adjust to the temperature of their outside environment rather than developing body fat and eating large quantities of calories to keep themselves warm.
This allows fish to consume fewer calories in order to survive and the lack of body fat/blubber allow them to stay slim remain extremely mobile in the water.
Additional facts about mammals
- Mammals can vary significantly in terms of size ranging from 1 inch (the bumblebee bat) to over 90 ft. long and 150 tons (the blue whale).
- With the exception of the monotreme species (which lays eggs) almost all mammals give birth to their young.
- Mammals are warm-blooded animals and have developed body fat or blubber in order to hunt and survive in cold regions that otherwise would be inhabitable for them.
- Some mammals have evolved over many millennium from four-legged animals to two legged animals, and some species such as whales developed flipper and flukes in order to survive in the ocean.
- Most mammals produce consistent body heat which burns energy and requires them to eat nutrient rich foods which contain essential fats and proteins on a regular basis in order to maintain their body fat and internal temperature.
- Some mammals such as the humpback whale will eat a large amounts of food during their feeding season and survive off of their energy and fat by fasting during their mating season.
- Humans and other animals are also known to develop layers of fat in order to provide them with additional calories and energy during times when food is scarce.
- There are currently around 5,500 species of mammals that have been recorded so far (as of 2011) and the list keeps growing!