Being that dolphins look like fish and resemble many other large sea creatures people are usually shocked to find out that they are in fact mammals. This can be a confusing concept to get your head around, especially since dolphins have a similar appearance to sharks (sharks are actually a type of fish). While you’re not likely to have any dolphins come up in your Ancestry.com test results, they do have some key features that make them a distinct part of the mammal family.
Why are dolphins considered mammals?
To be considered a mammal, you have to possess some specific traits such as…
- Being warm-blooded. Which means you can regulate your own body temperature.
- Have live babies. Meaning to not lay eggs but rather birth live offspring instead.
- Be able to produce milk. Mammals produce their own milk supply to give nourishment to their young.
- Breathe air. All mammals need oxygen to survive.
Dolphins are members of the Cetacea mammal family, along with whales and other porpoises. This is a group of animals that have adapted to live in water, and are found all over the world in the oceans (and some rivers!). Dolphins have been around for millions of years and it has been recently discovered that their ancestors may have surprisingly lived on land.
Dolphins possess all of the characteristics which classify them as mammals. Even though they are in fact mammals, there are some things that make them stand apart from “typical” mammals.
Even though they do breathe oxygen and have lungs, they don’t breathe the air from their mouths but rather their blowholes which is a separate path to their lungs located on the top of their heads. This is so when they do hunt or eat, water cannot fill their lungs…potentially drowning them. Dolphins have large lungs which help them to be able to spend significant time underwater unlike other mammals.

Another known mammal characteristic is the appearance of hair. Although dolphins typically don’t have hair they do however have hair follicles. The animal group cetacea is also closely related to hooved animals such as hippos with those species containing hair.
Where do Dolphins Live?
Dolphin species live in all oceans all over the world and in certain important rivers. The well-known bottle-nosed dolphin lives in every ocean except the Arctic or Antarctica oceans. Not all species of dolphins live in the same areas but there are different species living in all environments. culvers coupons
What do Dolphins eat?
Different species of dolphins eat different things. Larger species such as orcas will eat marine mammals like seals and sea lions. Bottle-nosed dolphins will eat fish such as herring, mackerel, cod and sometimes squid. Dolphins use a herding method to hunt where a pod will chase fish into a certain area while they take turns eating as they are grouped together.
How many different species of dolphins are there?
As of right now, there are 49 dolphin and porpoises species. These species are classified into 6 groups with 2 being oceanic dolphin groups and 4 groups of river dolphins. This is a large species that can sometimes be confusing and many people mistaking types of dolphins all the time.
So, to answer the question of why dolphins are considered mammals all boils down to their characteristics. Dolphins and porpoises share all of the traits of mammals with ancestors dating back millions of years and studied to be land animals that adapted to the aquatic lifestyle. Dolphins are animals that breath air, are warm-blooded, produce live offspring, and produce milk. Dolphins are a very important part of our ocean eco-system and must be protected to ensure our ocean stability for years to come.
Fun/Interesting Facts about Dolphins:
- Dolphins are highly intelligent animals.
- Dolphins communicate with sounds such as clicking or whistling.
- It is said that dolphin’s sonar capabilities are superior to bats and even man-made sonar equipment.
- Killer whales (orcas) are actually dolphins.
- Sleeping dolphins have to stay near the water surface to not cover their blowholes.
- Also while sleeping, dolphins will only switch off a part of their brain for the ability to stay alert and to breath.
- Bottlenose dolphins are the most common species.
- Male dolphins are called bulls as with females being called cows. Baby’s are appropriately named calves.
- Many fishing methods are the cause of death in dolphins as they often get caught in nets.