The false killer whale was known only from a fossil skull until carcasses washed up
Richard Owen described this animal in 1846 from a skull dug out of the Lincolnshire Fens and took it for a kind of porpoise. Scientists assumed it was extinct until bodies came ashore in Kiel Bay in 1861. It turned out to be a large oceanic dolphin that roams tropical seas in tight-knit pods.
The fossil skull came from a marine deposit about 126,000 years old and was later lost. Owen nicknamed the creature the thick-toothed grampus, which is what crassidens means. After the Kiel Bay strandings and a second beached pod three months later, the Danish zoologist Johannes Reinhardt created a new genus for it in 1862, Pseudorca, marking it as neither a porpoise nor a true killer whale. The common name reflects a skull that resembles the orca's.
Only the orca and the two pilot whales are bigger among oceanic dolphins. Males reach 6 m and about 2,200 kg, females up to 5 m and 1,200 kg. They hunt squid and big fish such as tuna, mahi-mahi and wahoo by day, sometimes discard the tail and gills, share food within the pod and will take other dolphins; in 2025 more than 50 were reported attacking two humpbacks at once. One tagged near Hawaii dived to 927.5 m.
Social ties run deep. Groups of 10 to 20 are typical, though gatherings can exceed 500, and individuals have stayed with the same pod for 15 years in what appears to be a mother-led structure. They mix peacefully with bottlenose dolphins and pilot whales, answer distress calls, help remove afterbirth, and can hybridise with bottlenose dolphins to produce fertile wholphins. That closeness also drives mass strandings, the largest being more than 800 animals at Mar del Plata in 1946, and much of the science comes from stranded bodies.
Like pilot whales, females live long after menopause, which usually arrives between 45 and 55, and captive animals have reached 57 for males and 62 for females. Pregnancy lasts roughly 15 months. The Hawaiian population fell by an estimated 75% between 1989 and 2009, likely because the whales steal fish from longline hooks and get entangled or swallow the hooks; some even offer their catch to divers.
Source: False killer whale
