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 have soft, hair like structures on the upper mouth. What this does is allow them to trap their prey into their mouths without escaping resembling a net. This is known as a filter feeding. Whales were the first mammals to evolve baleen and no other mammal uses any anatomical structures such as this to catch their prey. Baleen has a similar chemical to the composition of hair and fingernails than any type of bone, so it does not fossil well. It is rare to see a fossil of a whale with baleen intact. 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 species3 familiesLarger than the toothed whalesHave baleen plates in their mouths that sieve water for foodSwim through the water with their mouths open to gather food2 blowholesSwim/live alone or in small groupsDo not echolocate, but do make sounds to communicateMost baleen whales are migratory

In total baleen whales include the following species:

Bowhead whaleSouthern right whaleNorthern Atlantic right whaleNorth Pacific right whalePygmy right whaleCommon minke whaleSouthern minke whaleGray whaleHumpback whaleBlue whaleFine whaleOmura’ whaleEden’s whaleRice’s whaleSei whaleBryde’s whale

Toothed Whales (Odontceti)

76 species10 familiesSmaller than baleen whalesHave teethActively hunt prey1 blowholeSwim/live in groups called podsUse echolocation, make sounds to communicateTypically 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 speciesOcean dolphinsIncludes the common bottlenose dolphin, spinner dolphin and killer whale* +36 more

Dolphin Family 2: Iniidae Dolphin Family 3: Platanistidae

2 speciesRiver dolphinsGanges River dolphins and Indus River dolphins

Dolphin Family 4: Pontoporiidae

Only 1 speciesOcean dolphins, live in estuaries along the coastFranciscana dolphins

Dolphin Family 5: Lipotidae (Possibly Extinct)

Only 1 speciesRiver DolphinBaiji 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).

Here is a list of dolphins (species in the Delphinidae family) with tricky names

While many of these have the word “whale” in their name they resemble more closely dolphins and are in the dolphin family.

killer whale or orcafalse killer whalepygmy killer whalemelon-headed whalelong-finned pilot whaleshort-finned pilot whalenorthern right whale dolphinsouthern 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:

  1. Dolphin Family 1: Delphinidae

39 speciesOcean dolphinsIncludes the common bottlenose dolphin, spinner dolphin and killer whale* +36 more

  1. Dolphin Family 2: Iniidae
  2. Dolphin Family 3: Platanistidae

2 speciesRiver dolphinsGanges River dolphins and Indus River dolphins

  1. Dolphin Family 4: Pontoporiidae

Only 1 speciesOcean dolphins, live in estuaries along the coastFranciscana dolphins

  1. Dolphin Family 5: Lipotidae (Possibly Extinct)

Only 1 speciesRiver DolphinBaiji dolphin (It is listed as “Critically Endangered/Possibly Extinct” by the IUCN)

  1. Porpoise Family: Phocoenidae

7 speciesHarbor porpoise, Spectacled porpoise, Indo-Pacific finless porpoise +4 moreFun 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.

  1. Sperm whale Family: Physeteridae

1 speciesSperm whale

  1. Pygmy sperm whale Family: Kogiidae

2 speciesPygmy sperm whale, dwarf sperm whale

  1. Beluga and Narwhal Family: Monodontidae

2 speciesBeluga (white whale), Narwhal

  1. Beaked whale Family: Ziphiidae

23 speciesCuvier’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 speciessouthern right whale, North Atlantic right whale, North Pacific right whale, bowhead whale

  1. Pygmy Right Whale Family: Neobalaenidae

1 speciesPygmy right whale

  1. Gray Whales: Eschrichtiidae

1 speciesGray Whale

  1. Rorqual Whale Family: Balaenopteridae

9 speciesLargest whalesHumpback, blue, fin, sei, common minke, Antarctic minke, Bryde’s, Omura’s, and Rice’s

What about Whale Sharks? (Just to make things interesting!)

Just when you thought you had it all figured out! What about the whale shark? It doesn’t appear on any of these lists so is it a whale? Is it a shark? 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.