You might see dolphins on one of our sea adventures. Cindy Rasmussen for A-Z Animals on how dolphins and whales are related.
Whales are the biggest animal on the planet, dolphins are comparably smaller, but are they all one “big” happy family? They all belong to the Order Cetacea which is the group of sea mammals that includes whales, dolphins and porpoises. To be a part of the Cetacea Order you must have the following characteristics: completely aquatic, streamlined body, front flippers, no hind limbs, tail with a horizontal fin and usually hairless.
Next the Order Cetacea is broken into 2 suborders, Mysticeti (Baleen Whales) and Odontceti (Toothed Whales). You may have been thinking that the suborders would be whales, dolphins and porpoises (that would have made this article short and sweet) but remember classifications are based on characteristics of the animal and the names can be misleading sometimes. Let’s look at these two suborders and then we will look at the families of each suborder.
Are Dolphins Whales?
To put it succinctly, dolphins are whales! All species in the Cetacea order are classified as whales. As you’ll read more about below, most of the distinction between dolphins, porpoises, and smaller whales occurs among toothed whales. We’ll first explore the larger baleen whales and then dig into the differences among toothed whales.
Baleen Whales (Mysticeti)
Baleen whales include some of the largest whale species on the planet. Blue whales, fin whales, and humpbacks are all part of the baleen whale suborder. While baleen whales are some of the largest animals to ever live on Earth, they also feed on massive amounts of incredibly small food sources such as plankton and krill.
- 16 species
- 3 families
- Larger than the toothed whales
- Have baleen plates in their mouths that sieve water for food
- Swim through the water with their mouths open to gather food
- 2 blowholes
- Swim/live alone or in small groups
- Do not echolocate, but do make sounds to communicate
- Most baleen whales are migratory
In total baleen whales include the following species:
- Bowhead whale
- Southern right whale
- Northern Atlantic right whale
- North Pacific right whale
- Pygmy right whale
- Common minke whale
- Southern minke whale
- Gray whale
- Humpback whale
- Blue whale
- Fine whale
- Omura’ whale
- Eden’s whale
- Rice’s whale
- Sei whale
- Bryde’s whale
Toothed Whales (Odontceti)
A dolphin’s communication and decision-making skills often draw comparisons with humans.
- 76 species
- 10 families
- Smaller than baleen whales
- Have teeth
- Actively hunt prey
- 1 blowhole
- Swim/live in groups called pods
- Use echolocation, make sounds to communicate
- Typically do not migrate
So what suborder do dolphins belong to? They are toothed whales! So dolphins are whales. The toothed whale suborder is broken down into 10 families and 5 of those families include dolphins.
Dolphin Family 1: Delphinidae
- 39 species
- Ocean dolphins
- Includes the common bottlenose dolphin, spinner dolphin and killer whale* +36 more
Dolphin Family 2: Iniidae
- Only 1 species
- River dolphin
- Amazon River Dolphin (Pink Dolphin)
Dolphin Family 3: Platanistidae
- 2 species
- River dolphins
- Ganges River dolphins and Indus River dolphins
Dolphin Family 4: Pontoporiidae
- Only 1 species
- Ocean dolphins, live in estuaries along the coast
- Franciscana dolphins
Dolphin Family 5: Lipotidae (Possibly Extinct)
- Only 1 species
- River Dolphin
- Baiji dolphin (It is listed as “Critically Endangered/Possibly Extinct” by the IUCN)
Killer whales are actually dolphins…AND toothed whales!
- This is where it gets tricky. All dolphins are in one of these 5 families. All 5 of these families are in the toothed whale suborder so that means dolphins are toothed whales. Killer whales, and a handful of other species with the word “whale” in their name, are dolphins because they share the same characteristics. Killer whales (orcas) are much smaller than whales like the Sperm whale (which is also a toothed whale) and they resemble dolphins more with their sleek bodies and dorsal fins. They are the largest species in the Delphinidae family with some growing to be 32 feet long. So technically they are both dolphins (family) and toothed whales (suborder). killer whale or orca
- false killer whale
- pygmy killer whale
- melon-headed whale
- long-finned pilot whale
- short-finned pilot whale
- northern right whale dolphin
- southern right whale dolphin
Fun Fact about the Northern Right Whale Dolphin
According to the NOAA, “Northern right whale dolphins are the only species of dolphin in the North Pacific Ocean without a dorsal fin.”
What are the 10 Families of Toothed Whales?
Here is a list of all of the toothed whale families, starting with the 5 dolphin families we already looked at:
Dolphin Family 1: Delphinidae
- 39 species
- Ocean dolphins
- Includes the common bottlenose dolphin, spinner dolphin and killer whale* +36 more
2. Dolphin Family 2: Iniidae
- Only 1 species
- River dolphin
- Amazon River Dolphin (Pink Dolphin)
3. Dolphin Family 3: Platanistidae
- 2 species
- River dolphins
- Ganges River dolphins and Indus River dolphins
4. Dolphin Family 4: Pontoporiidae
- Only 1 species
- River Dolphin
- Baiji dolphin (It is listed as “Critically Endangered/Possibly Extinct” by the IUCN)
5. Dolphin Family 5: Lipotidae (Possibly Extinct)
- Only 1 species
- River Dolphin
- Baiji dolphin (It is listed as “Critically Endangered/Possibly Extinct” by the IUCN)
6. Porpoise Family: Phocoenidae
- 7 species
- Harbor porpoise, Spectacled porpoise, Indo-Pacific finless porpoise +4 more
- Fun Fact: Dolphins and porpoises look a lot alike but they have distinct differences. The most telling is the longer snout (or beak) of the dolphin, porpoises have a more rounded face. Dolphins are larger than porpoise and have a slimmer body line. Dolphins’ dorsal fin is more curved where the porpoises’ is more triangular.
7. Sperm whale Family: Physeteridae
- 1 species
- Sperm whale
8. Pygmy sperm whale Family: Kogiidae
- 2 species
- Pygmy sperm whale, dwarf sperm whale
9. Beluga and Narwhal Family: Monodontidae
- 2 species
- Beluga (white whale), Narwhal
10. Beaked whale Family: Ziphiidae
- 23 species
- Cuvier’s beaked whale, Baird’s beaked whales, Blainville’s beaked whale +20 more
What about Baleen whales, are any dolphins also Baleen whales?
Baleen whales (Mysticeti) are sea animals that have baleen instead of teeth. Baleen is long whisker-like strands that form along the jaw-line and are used to filter for small fish, crustaceans, krill and plankton. Baleen whales are also much larger than toothed whales being the largest animals in the world. Just like toothed whales, baleen whales are broken down into families. There are 4 baleen whale families. All dolphins have teeth, none have baleen and the largest dolphin is “only” 32 feet long, so there are no dolphins in any of the baleen whale families.
What are the 4 Baleen Whale Families?
1. Right Whale Family: Balaenidae
- 4 species
- southern right whale, North Atlantic right whale, North Pacific right whale, bowhead whale
2. Pygmy Right Whale Family: Neobalaenidae
- 1 species
- Pygmy right whale
3. Gray Whales: Eschrichtiidae
- 1 species
- Gray Whale
4. Rorqual Whale Family: Balaenopteridae
- 9 species
- Largest whales
- Humpback, blue, fin, sei, common minke, Antarctic minke, Bryde’s, Omura’s, and Rice’s
What about Whale Sharks? (Just to make things interesting!)
Whale sharks are actually sharks, not whales. They are called whale sharks because they are large (like whales) and sieve water for food like plankton (like whales), but they have gills (like sharks) and cartilage (like sharks). One of the biggest distinctions is that whales are mammals and sharks are fish. So although the whale shark has some similar characteristics they clearly belong with their fellow sharks.
Hopefully that clears things up about how dolphins and whales are related. You can understand why these fascinating sea creatures draw so much attention and are a wonder to watch. With many Marine Life Management organizations and ongoing diligence of conservationist we can hope future generation will ask if dolphins are actually whales as well.
