01/08/2026
🔬Science Saturday🔬
Porpoise Anatomy
🐬Black lips and chin – Harbour porpoise do not have a beak, they have a blunt, rounded rostrum with black lips and chin.
🐬Spatulate, homodont teeth – identical, spade-shaped teeth (between 38 and 56 in each jaw), used for catching prey not chewing.
🐬Melon – located in the forehead, indistinguishable from the rostrum due to lack of beak and much smaller than in other cetaceans. Fatty organ used for echolocation, by processing high frequency, short duration clicks.
🐬Blowhole – single, crescent shaped blowhole located on top of their head. Sealed by strong muscle when underwater to prevent water from entering the lungs. They make a puffing sound when they come up for air.
🐬Dorsal Fin – short, triangular dorsal fin with a wide base set just past the centre of their back. Has the same function as in dolphin species, stabilisation and thermoregulation.
🐬Pectoral fins – short, rounded fins on either side of their body just behind the head. Act as a hydrofoil and are used for steering, breaking and generating lift when surfacing and flattening against the body to reduce drag during high-speed swimming.
🐬Peduncle – area between the dorsal fin and tail flukes. Comprised solely of muscle tissue and robust tendons it transfers core muscle power to the tail flukes for propulsion.
🐬Tail Flukes – small and curved with a median-notch. Used to propel the porpoise through the water, powered by the peduncle.
🐬Robust, fusiform body – the smallest species of small-toothed whale in the world, Harbour porpoise can reach up to 1.9 meters in length. They are much more robust and stockier than a dolphin but are also fusiform (wider in the middle, narrowing at both ends). Their backs are usually dark grey-brown and their underside is usually a greyish-white.
Credit and verification of information – NOAA, Cornwall Mammal Group, Hebridean Whale and Dolphin Trust, Porpoise Conservation Society, Whale and Dolphin Conservation, BDMLR, Hunt et al., 2019 (Advanced Intelligent Systems, 1(4)), SeaWatch Foundation, MarLIN, COSEWICK.
