Mammal
Blue Whale
The largest animal that has ever lived
Species group · 9 profiles
Whales and Dolphins
Nine whale and dolphin profiles — blue whale to bottlenose and orca. Cetacean facts, size, diet and conservation.
Quick answer
Whales and dolphins are marine mammals of the order Cetacea — air-breathing, warm-blooded and milk-feeding, fully adapted to life in water. This guide profiles nine species: blue whale, humpback whale, sperm whale, fin whale, minke whale, beluga whale, orca, narwhal and bottlenose dolphin. The blue whale is the largest animal known to have lived, reaching about 25–30 metres (82–98 ft) and roughly 100–150 tonnes. The orca is the largest living dolphin. Whale sharks are cartilaginous fishes and appear on the sharks hub, not here. Profiles cover diet guilds, seasonal migration patterns, pod social structure, acoustic behaviour and IUCN conservation status.
Whales and Dolphins in this guide
Mammal
Humpback Whale
The acrobatic singer of the seas
Mammal
Sperm Whale
The deep-diving giant with the largest brain
Mammal
Fin Whale
The sleek greyhound of the seas
Mammal
Minke Whale
The smallest and most abundant rorqual
Mammal
Beluga Whale
The white whale of the Arctic
Mammal
Orca
The ocean's top predator
Mammal
Narwhal
The tusked unicorn of the sea
Mammal
Bottlenose Dolphin
One of the ocean's most intelligent animals
Telling them apart
Dolphins are whales in the broad cetacean sense — specifically toothed whales in families such as Delphinidae. The orca (killer whale) is the largest dolphin, not a baleen whale. Baleen whales filter plankton and small schooling prey; toothed whales hunt fish, squid or marine mammals. Whale sharks belong with sharks, not Cetacea, despite the shared English word "whale" in their common name.
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Whales and Dolphins: common questions
Is an orca a whale or a dolphin?
Both labels apply in ordinary speech; taxonomically the orca is the largest member of the oceanic dolphin family (Delphinidae) and a toothed whale within Cetacea. Adults commonly reach 6–8 metres (20–26 ft). Diet and hunting culture vary by ecotype — fish specialists versus mammal hunters.
Are dolphins whales?
Yes. Dolphins are cetaceans — specifically toothed whales. "Whale" in everyday English often means only the large baleen species, which creates a false split. Bottlenose dolphins, orcas and related delphinids share the same mammalian order as blue and humpback whales.
What is the largest whale?
The blue whale is the largest animal on record, about 25–30 metres (82–98 ft) long and 100–150 tonnes. Fin whales are the second-longest living species. Blue whales feed mainly on krill strained through baleen plates rather than by biting large prey.
Is a whale shark a whale?
No. The whale shark is a filter-feeding shark — the largest living fish — and is listed on the sharks hub. It has gills and a cartilaginous skeleton. Cetaceans on this page are mammals that surface to breathe air through blowholes.