Harbour porpoise: The shy 'sea pig' of coastal waters

The harbour porpoise is one of the smallest members of the whale family — and the easiest to miss at the coast, because it is so shy, surfacing with only a soft puff that many people never notice. Sailors nicknamed it the "sea pig". Let's meet it.

Its body

The harbour porpoise measures about 1.4 to 1.9 metres. It is a cousin of the dolphins but built differently: smaller, with a shorter, blunter beak and teeth shaped like little spades rather than a dolphin's cones. Its body is rounded, its dorsal fin triangular, and it is mostly dark grey.

Its personality and skills

The harbour porpoise is shy by nature. It hardly ever leaps and does not ride bow waves the way dolphins do, and when it surfaces to breathe it gives only a short "puff" — the very sound that earned it the "sea pig" nickname. In murky coastal water it hunts small fish and shrimps by echolocation: it makes sounds and listens to the echoes, "seeing" its surroundings with sound.

The threats it faces

For the harbour porpoise, the greatest danger is entanglement in fishing nets, where it is often caught by accident. The good news is that many fishing fleets now fit acoustic "pingers" to their nets, making sounds the porpoise can hear to warn it away. Such small technical improvements are helping it survive.

A note for grown-ups

You could talk with a child about how big the smallest whale is — the harbour porpoise is shorter than an adult human. Then ask: why does it not like coming near boats? Because it is shy. Helping a child understand that every animal has its own temperament is the first step in respecting life.