Phocoena – Harbor porpoises

Harbor porpoises are small, elusive marine mammals that play a significant role in the marine ecosystems of the Northern Hemisphere. Due to their similar size and aquatic habitats, these animals are often mistaken for their more famous cousins, the dolphins. However, despite their apparent similarities and shared ancestry, dolphins and porpoises have diverged significantly over nearly eleven million years of evolution, resulting in distinct differences in morphology, behavior, and ecology.

One key distinction between dolphins and porpoises is their physical appearance. Harbor porpoises have a more robust body shape, smaller size, and a rounded head without the prominent beak found in many dolphin species. Their dorsal fins are also smaller and more triangular than dolphins’ sickle-shaped fins. These characteristics can help observers distinguish between the two in the wild, although the confusion between dolphins and porpoises persists in common conversation.

Harbor porpoises have a wide distribution, inhabiting coastal waters and estuaries across North and South America, Europe, and parts of Asia, including the Mediterranean and the Black Sea. Unlike some of their relatives, harbor porpoises prefer cooler temperate and subarctic waters and are rarely found in tropical or subtropical regions. Their preference for shallow, coastal areas makes them more susceptible to human impacts, including pollution, habitat degradation, and accidental bycatch in fishing gear.

As predators, harbor porpoises play a crucial role in maintaining the balance of marine ecosystems. They primarily feed on small fish, squid, octopus, and other mollusks. The specific diet of a harbor porpoise varies depending on its location, reflecting the biodiversity of its habitat. This adaptability in the diet allows harbor porpoises to thrive in a variety of marine environments, from open seas to more confined bays and estuaries.