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Animal Comparison

Dolphin vs Porpoise

Dolphins have long, beaked snouts, curved dorsal fins and cone-shaped teeth; porpoises have blunt faces, triangular fins and spade-shaped teeth. Full comparison.

By the WARN Research & Conservation TeamChecked against IUCN Red List & CITES sourcesLast updated

In brief — Dolphin vs Porpoise

If it has a beak and cone-shaped teeth, it is a dolphin; if it has a blunt face and spade-shaped teeth, it is a porpoise.

The clearest difference is head and tooth shape: dolphins have an elongated, beak-like snout with cone-shaped (conical) teeth, while porpoises have a blunt, beakless face with flat, spade-shaped teeth. Dolphins also tend to have taller, curved dorsal fins and leaner bodies, whereas porpoises have smaller, triangular fins and stockier builds. Both are toothed whales (Odontoceti), but they belong to separate families: Delphinidae (dolphins) and Phocoenidae (porpoises).

See the difference

Dolphin: beaked snout, curved fin, conical teeth.

Dolphin — beaked snout, curved fin, conical teeth

Source: Wikimedia Commons

Harbour porpoise surfacing in calm sea, showing its small dark triangular dorsal fin and blunt back.

Porpoise — blunt head, triangular fin, spade-shaped teeth

Photo: Ben Phalan / Wikimedia Commons (CC BY 4.0)

Dolphin vs Porpoise: At a Glance

Feature Dolphin Porpoise
Family Delphinidae (oceanic dolphins) Phocoenidae (porpoises)
Number of species About 38, plus 5 river dolphin species 6-7 species
Snout shape Long, protruding beak (rostrum) Short, blunt, no distinct beak
Teeth Cone-shaped (conical), pointed Flat, spade-shaped
Dorsal fin Tall, curved (falcate) Small, triangular, less curved
Typical body size 2-4 m (6.6-13 ft); largest is the orca at up to 9 m 1.4-2.3 m (4.6-7.5 ft); smaller overall
Typical lifespan 40-60 years (bottlenose dolphin) 8-13 years on average (harbour porpoise)
Group behaviour Highly social, pods often 10-100+ Often solitary or in small groups of 2-8
IUCN status (example species) Least Concern (common bottlenose dolphin) Least Concern overall; vaquita Critically Endangered

Which is bigger & stronger?

Dolphins are generally bigger, with the common bottlenose reaching 2-4 m and up to 300-500 kg, whereas the harbour porpoise is typically only about 1.5-1.8 m and 50-70 kg.

Dolphins and porpoises are often confused because both are small, air-breathing, toothed whales (suborder Odontoceti) that live in social groups and use echolocation to hunt. But they are separated into two distinct families that diverged millions of years ago: Delphinidae, the oceanic dolphins, with around 38 species including the common bottlenose and orca; and Phocoenidae, the porpoises, a much smaller family of six or seven species including the harbour porpoise and the critically endangered vaquita. The clearest field marks are the shape of the snout and teeth, though fin shape, body build and typical group size also help tell them apart at sea.

Snout, teeth and facial shape

The most reliable way to tell them apart is the face. Dolphins have an elongated rostrum that forms a visible "beak" separated from the melon (forehead) by a crease, and their jaws hold numerous cone-shaped, pointed teeth suited to grasping fast-moving fish and squid. Porpoises lack a pronounced beak; their snout is short and rounded, blending smoothly into a blunter head profile, and their teeth are flattened and spade-shaped rather than conical. This tooth shape is the origin of the scientific distinction between the two families and is often the feature used to confirm identification from a stranded or captured animal.

Dorsal fin and body shape

Most dolphins carry a tall, curved (falcate) dorsal fin and a comparatively lean, streamlined body, features easy to spot when a bottlenose dolphin surfaces and arcs through a wave. Porpoises have a smaller, more triangular dorsal fin with little to no backward curve, set on a stockier, more compact body. Because porpoises surface briefly and with a low-key roll rather than dramatic leaps, their fin shape combined with a quieter surfacing style is often the quickest visual cue at sea, even before facial features are visible.

Size, lifespan and social behaviour

Dolphins are generally larger and longer-lived: the common bottlenose dolphin measures 2-4 m (6.6-13 ft) and can live 40-60 years, while the family's largest member, the orca, reaches up to 9 m (30 ft). Porpoises are smaller and shorter-lived, typically 1.4-2.3 m (4.6-7.5 ft) with an average lifespan of 8-13 years in species such as the harbour porpoise. Dolphins are famously gregarious, travelling in fission-fusion pods that can number in the hundreds and communicating with complex whistles and clicks. Porpoises are typically more solitary or found in small, loose groups of two to eight, and are generally quieter and more elusive around boats.

Diversity and conservation status

Dolphins form a much larger and more diverse family, Delphinidae, with roughly 38 recognised oceanic species (plus five separate river dolphin species in other families) found in every ocean and many major rivers. Porpoises belong to the far smaller family Phocoenidae, comprising just six or seven species confined mainly to cooler coastal and temperate waters. Most dolphin and porpoise species are currently listed as Least Concern by the IUCN, but conservation status varies sharply by species: the vaquita, the world's smallest porpoise, found only in Mexico's northern Gulf of California, is Critically Endangered, primarily due to entanglement in fishing gear, while several river dolphin species are also at serious risk.

Did you know?

The vaquita, the world's smallest and most endangered porpoise, was only discovered by science in 1958 and lives in a single, tiny stretch of Mexico's northern Gulf of California, an area smaller than many cities.

Dolphin vs Porpoise: FAQs

Is a porpoise a type of dolphin?
No. Although both belong to the toothed-whale suborder Odontoceti, porpoises and dolphins are separate families, Phocoenidae and Delphinidae respectively, that diverged millions of years ago. A porpoise is not a dolphin, though the terms are sometimes used loosely in everyday speech.
Which is bigger, a dolphin or a porpoise?
Dolphins are generally bigger. A common bottlenose dolphin measures 2-4 m (6.6-13 ft), and the largest dolphin, the orca, can reach 9 m (30 ft). Most porpoises are smaller, typically 1.4-2.3 m (4.6-7.5 ft), with the vaquita the smallest cetacean of all at up to 1.5 m (4.9 ft).
How can you tell a dolphin and a porpoise apart in the water?
Look at the dorsal fin and snout. Dolphins show a tall, curved fin and a protruding beak-like snout, often leaping clear of the water. Porpoises have a small, triangular fin, a blunt beakless face, and surface in a quick, low roll rather than leaping.
Do dolphins and porpoises interbreed?
Dolphins and porpoises belong to different families and do not interbreed with each other. Hybridisation is documented within dolphins (for example between bottlenose dolphins and other Delphinidae species) but not across the dolphin-porpoise family divide.
Are porpoises endangered?
Most porpoise species are listed as Least Concern by the IUCN, but this varies by species and population. The vaquita, found only in Mexico's Gulf of California, is Critically Endangered with a population reduced to roughly a few dozen individuals, chiefly due to bycatch in illegal gillnets.
What is the difference between dolphin and porpoise teeth?
Dolphin teeth are cone-shaped and pointed, an adaptation for gripping slippery prey such as fish and squid. Porpoise teeth are flattened and spade-shaped. This tooth-shape difference is one of the defining anatomical features separating the two families.

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