The term whale sometimes refers to all cetaceans. Cetaceans are divided into two suborders: Mysticeti and Odontoceti. Mysticeti whales are also called baleen whales; they have plates of baleen, made of keratin, suspended from their upper jaw that filter plankton and krill from the water. Odontoceti refers to the toothed whales, which are carnivorous and eat fish, sea lions, and sometimes other whales.
Like all mammals, whales are warm-blooded, breathe air, and feed their young milk. Whale size ranges enormously: the smallest, Hector's dolphin, is 3.25–5.25 feet in length, while the largest, the blue whale, grows to nearly 100 feet and 200 tons.
Baleen vs. Toothed Whales
The two whale suborders differ in feeding anatomy, size, diet, and social structure.
| Baleen (Mysticeti) | Toothed (Odontoceti) | |
|---|---|---|
| Teeth | No | Yes |
| Blow holes | Two | One |
| Size | Generally larger | Generally smaller |
| Diet | Krill & plankton | Fish, squid & marine mammals |
| Social structure | Often solitary | Developed pod structure |
| Known species | ~15 | Approx. 66 (incl. dolphins) |
Anatomy & Adaptations
Traits shared across whale species, shaped by life in open water.
Blowholes
Baleen whales surface through two blowholes; toothed whales through a single one, both sealed by muscular flaps that close automatically underwater.
Blubber
A thick layer of insulating fat — up to 17 inches in the bowhead whale — keeps body heat in and stores energy for migration and lean feeding seasons.
Echolocation
Toothed whales emit clicks and read the returning echoes to navigate and hunt in dark or murky water, some at frequencies far beyond human hearing.
Migration
Many species travel thousands of miles each year between cold feeding grounds and warm breeding waters, some of the longest journeys of any mammal.
Did You Know?
Whales are the hippopotamus's closest living relatives.
Whale Species
22 species profiled here, grouped by suborder.
Baleen Whales · Mysticeti
Blue Whales
Balaenoptera musculus
Fin Whales
Balaenoptera physalus
Sei Whales
Balaenoptera borealis
Bryde's Whales
Balaenoptera edeni
Common Minke Whales
Balaenoptera acutorostrata
Antarctic Minke Whales
Balaenoptera bonaerensis
Omura's Whales
Balaenoptera omurai
Humpback Whales
Megaptera novaeangliae
Gray Whales
Eschrichtius robustus
Bowhead Whales
Balaena mysticetus
North Atlantic Right Whales
Eubalaena glacialis
Toothed Whales · Odontoceti
Sperm Whales
Physeter macrocephalus
Pygmy Sperm Whales
Kogia breviceps
Dwarf Sperm Whales
Kogia sima
Orca Whales
Orcinus orca
False Killer Whales
Pseudorca crassidens
Pilot Whales
Globicephala macrorhynchus
Melon-Headed Whales
Peponocephala electra
Beluga Whales
Delphinapterus leucas
Narwhals
Monodon monoceros
Cuvier's Beaked Whales
Ziphius cavirostris
Baird's Beaked Whales
Berardius bairdii
Whale Gifts
Whale-themed gifts and apparel.
