Are killer whales whales?
Quick Answer
Technically, killer whales (orcas) are dolphins, not true whales—they belong to the oceanic dolphin family (Delphinidae). However, dolphins are a subset of toothed whales (Odontoceti), so orcas are 'whales' in the broader taxonomic sense. They're the largest member of the dolphin family.
Key Facts
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Quick Facts
| Attribute | Details |
|---|---|
| Type | Marine mammal |
| Family | Cetacea |
| Habitat | Oceans worldwide |
| Conservation | Protected in most countries |
| Research Status | Ongoing scientific study |
The Short Answer
The answer is both yes and no, depending on how you define “whale.” Taxonomically, killer whales (orcas) are dolphins—they belong to the family Delphinidae (oceanic dolphins) and are the largest member of this family. However, dolphins are a subgroup of toothed whales (Odontoceti), which means orcas are technically whales in the broader scientific sense. The common name “killer whale” predates modern taxonomy and has stuck despite being somewhat misleading.
The Taxonomy Explained
Orca Classification Hierarchy
| Level | Classification | What It Means |
|---|---|---|
| Kingdom | Animalia | Animals |
| Phylum | Chordata | Vertebrates |
| Class | Mammalia | Mammals |
| Order | Cetacea | Whales, dolphins, porpoises |
| Suborder | Odontoceti | Toothed whales |
| Family | Delphinidae | Oceanic dolphins |
| Genus | Orcinus | Orcas only |
| Species | O. orca | Killer whale |
The key distinction is at the family level: orcas belong to Delphinidae (dolphins), not to whale families like Balaenopteridae (rorquals) or Physeteridae (sperm whales).
What Makes Something a “Whale”?
| Definition | Is Orca Included? | Explanation |
|---|---|---|
| Order Cetacea (all cetaceans) | Yes | Orcas are cetaceans |
| Suborder Odontoceti (toothed whales) | Yes | Orcas are toothed whales |
| Non-dolphin cetaceans | No | Orcas are dolphins |
| ”Large cetaceans” (common usage) | Yes | Orcas are large (32 ft) |
| Scientific “whale families” | No | Orcas are in dolphin family |
Dolphins vs. Whales: Key Differences
Physical Characteristics
| Feature | Dolphins (including orcas) | “True” Whales |
|---|---|---|
| Teeth | Conical teeth | Baleen or large teeth |
| Snout | Usually pronounced beak | Blunt or no beak |
| Dorsal fin | Curved or triangular | 50,000 worldwide widely |
| Body shape | Streamlined | Often robust |
| Neck vertebrae | Fused | Often fused |
| Size range | 4-32 ft | 8-100 ft |
Behavioral Differences
| Behavior | Dolphins | Baleen Whales |
|---|---|---|
| Echolocation | Yes, advanced | No |
| Hunting | Active predation | Filter feeding |
| Social structure | Complex pods | Loose groups |
| Communication | Whistles, clicks | Songs, calls |
| Speed | Fast, agile | Slower, powerful |
Orcas exhibit classic dolphin characteristics: advanced echolocation, complex social structures, and active predation.
Why Are They Called “Killer Whales”?
Historical Naming Timeline
| Era | What Happened | Result |
|---|---|---|
| Pre-1700s | All large marine mammals called “whales” | Orcas = whales |
| 1700s | Spanish sailors observe orca hunting | ”Whale killer” |
| 1700s | Name reversed in English | ”Killer whale” |
| 1758 | Linnaeus names genus Orcinus | Scientific classification |
| 1900s | Family Delphinidae defined | Orcas = dolphins taxonomically |
| Present | Both names used | ”Orca” or “killer whale” |
The name “killer whale” was established long before scientists understood that orcas were dolphins. By the time taxonomy clarified the relationship, the common name was too embedded to change. Learn more at why are killer whales called killer.
Orcas Compared to Other Family Members
The Dolphin Family (Delphinidae)
| Species | Maximum Size | Relation to Orca |
|---|---|---|
| Orca | 32 ft (9.8m) | Largest dolphin |
| Pilot whale (long-finned) | 25 ft (7.6m) | Second largest |
| False killer whale | 20 ft (6m) | Third largest |
| Bottlenose dolphin | 13 ft (4m) | Most well-known dolphin |
| Common dolphin | 8 ft (2.4m) | Abundant species |
| Spinner dolphin | 7 ft (2.1m) | Acrobatic species |
Despite being called “whales,” pilot whales and false killer whales are also dolphins in family Delphinidae.
Orcas vs. “True” Whales
| Feature | Orca | Sperm Whale | Blue Whale |
|---|---|---|---|
| Family | Delphinidae | Physeteridae | Balaenopteridae |
| Type | Toothed | Toothed | Baleen |
| Max length | 32 ft | 67 ft | 100 ft |
| Max weight | 12,000 lbs | 90,000 lbs | 400,000 lbs |
| Diet | Varied | Squid | Krill |
| Teeth/Baleen | 40-56 teeth | 20-26 teeth | Baleen plates |
| Echolocation | Yes | Yes | No |
| Social structure | Matrilineal pods | Female groups | Mostly solitary |
Frequently Asked Questions
If orcas are dolphins, why call them “killer whales”?
The name predates modern taxonomy. When 18th-century sailors named these animals, they called all large marine mammals “whales.” The specific name “killer whale” came from observing orcas hunting other whales. Although science now classifies orcas as dolphins, the traditional name persists. Many scientists and conservation organizations now prefer “orca.”
What’s the difference between an orca and a killer whale?
There is no difference—“orca” and “killer whale” are two names for the same species (Orcinus orca). “Orca” comes from the scientific name, while “killer whale” is the traditional English common name. Scientists increasingly prefer “orca” because it avoids implying danger to humans and is taxonomically neutral.
Are orcas more closely related to dolphins or whales?
Orcas are most closely related to dolphins. Within family Delphinidae, their closest relatives are pilot whales and false killer whales (both also misnamed as “whales”). Orcas are more distantly related to “true whales” like blue whales or sperm whales, which belong to different families within order Cetacea.
Why does the classification matter?
Understanding orca taxonomy matters for several reasons:
- Conservation: Different families have different legal protections
- Behavior: Dolphins and baleen whales have very different biology
- Evolution: Reveals orca ancestry and adaptations
- Education: Promotes accurate scientific understanding
Are there any other “whales” that are actually dolphins?
Yes, several species called “whales” are taxonomically dolphins:
| Species | Common Name | Actual Family |
|---|---|---|
| Pilot whale | ”Whale” | Delphinidae (dolphin) |
| False killer whale | ”Whale” | Delphinidae (dolphin) |
| Melon-headed whale | ”Whale” | Delphinidae (dolphin) |
| Pygmy killer whale | ”Whale” | Delphinidae (dolphin) |
The Broader Cetacean Family Tree
Simplified Cetacean Classification
| Suborder | Families | Examples | Common Names |
|---|---|---|---|
| Mysticeti (baleen whales) | 4 families | Blue, humpback, right | ”True” whales |
| Odontoceti (toothed whales) | 10 families | Sperm, orca, beaked | Whales + dolphins |
Within Odontoceti:
- Family Delphinidae: Orcas, dolphins, pilot whales
- Family Physeteridae: Sperm whales
- Family Ziphiidae: Beaked whales
- Family Monodontidae: Belugas, narwhals
- Family Phocoenidae: Porpoises
What Makes Orcas Unique
Despite being dolphins, orcas have several whale-like characteristics that contributed to their naming:
| Characteristic | Orca | Typical Dolphin | More Like |
|---|---|---|---|
| Size | 32 ft, 12,000 lbs | 6-8 ft, 400 lbs | Whales |
| Prey size | Seals, whales, sharks | Fish | Whales |
| Dorsal fin (male) | 6 ft tall, straight | 1-2 ft, curved | Unique |
| Coloration | Black and white | Gray/blue | Unique |
| Global range | All oceans | Usually tropical/temperate | Whales |
Orcas are essentially “super-dolphins”—the largest, most powerful, and most widely distributed member of their family.
For more orca information, see how long orcas live, why they’re called killer whales, and what orcas eat.
Related Questions
Sources & References
Last verified: 2026-02-02
People Also Ask
Why Are Killer Whales Called Killer??
Killer whales got their name from ancient sailors who observed them hunting and killing large whales. The original Spanish term 'asesina de ballenas' (whale killer) was later reversed to 'killer whale' in English.
How Old Do Orca Whales Live??
Female orcas live 50-80 years on average, with some reaching 100+ years. Male orcas have shorter lifespans of 30-50 years. The oldest known orca, Granny (J2), was estimated at 105 years old.
Do Killer Whales Eat Sharks??
Yes, killer whales eat sharks, including great white sharks. Orcas have developed specialized techniques to kill sharks, often flipping them upside-down to induce 'tonic immobility,' then extracting the nutrient-rich liver. When orcas arrive, great whites often flee the area.
How Fast Can A Killer Whale Swim??
Killer whales (orcas) can reach burst speeds of 34.5 mph (56 km/h), making them among the fastest marine mammals. Their cruising speed is typically 3-4 mph, but they can maintain 6-8 mph for extended periods during travel or hunting.
Test Your Knowledge: Orca
Lifespan: 50-80 years (females live longer)