What is the largest dolphin?
Quick answer
The largest species of dolphin is the orca, also called the killer whale. Adult males can grow to about 8 m (26 ft) long and weigh around 6 tonnes; females are smaller. Despite the name, orcas belong to the oceanic dolphin family (Delphinidae), and they’re the ocean’s top predator.
Key facts
- Scientific name
- Orcinus orca
- Length
- Males up to about 8 m (26 ft); females about 6–7 m
- Weight
- Up to about 6 tonnes
- Lifespan
- Females often 50+ years; some may live 80–90
Dolphin or whale?
All dolphins are toothed whales, a group that also includes porpoises and sperm whales. The orca is a member of the dolphin family, sharing features such as a beak-like snout, a curved dorsal fin and complex social behavior. Its dorsal fin is the tallest of any dolphin, up to 1.8 m in males.
Why “killer whale”?
Ancient sailors saw them hunting large whales and called them “whale killers.” Over time, the name flipped to “killer whale.” Wild orcas are not known to have killed humans.
Top of the food chain
Orcas have no natural predators. Different groups, called ecotypes, specialize in different prey:
| Ecotype | Main prey |
|---|---|
| Resident orcas (North Pacific) | Salmon |
| Transient (Bigg’s) orcas | Seals, sea lions, dolphins |
| Antarctic types | Penguins, seals, minke whales |
Some pods hunt as a team, creating waves to wash seals off ice floes, or even hunting great white sharks.
Families and dialects
Orcas live in close family groups called pods, often led by older females. Each pod has its own dialect of calls, passed down through generations. After menopause, grandmothers guide their pods to food, one of very few animals besides humans in which females live long after they stop reproducing.
Other big dolphins
| Species | Typical maximum length |
|---|---|
| Orca | ~8 m |
| Short-finned pilot whale | ~7 m |
| Long-finned pilot whale | ~6.5 m |
| False killer whale | ~6 m |
| Common bottlenose dolphin | ~4 m |
Pilot whales and false killer whales, despite their names, are dolphins too.
For the largest animal of all, see what the largest animal on Earth is.
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