Fin Whale

Fin whales gulp enormous mouthfuls of water and strain krill and fish through baleen plates — keratin fringes hanging from the upper jaw. They lunge-feed in productive upwellings and may cooperate loosely to concentrate prey. This is filter feeding at the scale of the second-largest animal on Earth, not the toothed hunting of sperm whales or orcas.

The right lower jaw is white, the left dark — a unique asymmetry whose function is debated, possibly related to corralling prey while swimming on their side. A prominent dorsal fin set far back gives a sleek profile unlike blue whales. The colour split is a field mark, not a wound or a paint job.

Fin whales migrate between high-latitude feeding grounds and lower-latitude breeding areas. Their low-frequency vocalisations carry hundreds of kilometres underwater and may help navigation or mate finding across ocean basins. Shipping noise sits in the same frequency neighbourhood, which is why ocean noise is a welfare issue for this species and not only a curiosity.

Industrial whaling decimated fin whales in the 20th century. Listed Vulnerable, populations are increasing in the North Atlantic and Southern Ocean where hunting has largely ceased, but ship strikes and entanglement remain significant threats. Vulnerable is a threatened category: recovery is real in some ocean basins and incomplete in others.

No. WARN does not operate marine mammal field teams. This guide is part of the free educational library. WARN’s marine-related appeals focus on sea turtles and habitat in partner-network countries; they are not a fin-whale census or a stranding network.