False killer whales, despite their intimidating name, are not actually whales but rather large, oceanic dolphins. The “killer” in their name originates from their predatory behavior on other marine mammals and a resemblance of their skull to that of true killer whales, also known as orcas. This article aims to clarify the nature of false killer whales and address common concerns regarding their potential danger to humans.
Characteristics and Behavior
False killer whales possess distinct physical attributes, featuring an entirely black or dark gray body. Their slender bodies are topped with a narrow, pointed head and a prominent, rounded forehead or “melon.” They have long, S-shaped flippers and a sickle-shaped dorsal fin. Adult males can reach lengths of up to 6.1 meters, while females are slightly smaller, growing up to 5 meters.
These dolphins are top predators, primarily consuming a diet of large fish and various squid species. They have also been observed preying on smaller dolphins, seals, sea lions, and even the calves of larger whales. False killer whales are highly social, forming strong, lasting bonds within pods typically ranging from 10 to 60 individuals, sometimes congregating into larger groups of hundreds. They engage in cooperative hunting strategies, working together to capture prey, and have been known to share food among pod members. They communicate through a complex system of clicks and whistles and are capable of deep dives, reaching depths of over 900 meters, and swimming at speeds up to 29 kilometers per hour.
Documented Human Interactions
Encounters between false killer whales and humans are generally characterized by curiosity and a lack of aggression. There are no widely known instances of false killer whales deliberately attacking humans. These marine mammals are known for their friendly and inquisitive nature, often approaching boats and divers. Documented observations include false killer whales swimming closely to people, twirling in the water near divers, and even presenting caught fish to humans, a behavior that mirrors their natural food-sharing practices within their pods.
While direct aggression towards humans is rare, false killer whales do interact with human activities, particularly fishing operations. They are known to take fish and bait directly from fishing lines, a behavior called depredation. This interaction can unfortunately lead to accidental hooking or entanglement in fishing gear, which poses a significant threat to their populations, especially in areas like the Hawaiian longline fishery. Injuries such as damage to their dorsal fins and mouthlines are frequently observed in false killer whales, likely resulting from these encounters with fishing equipment. False killer whales have also been kept in captivity, where they can be trained and form bonds with people, though their sometimes aggressive tendencies towards other dolphin species in these settings make them less commonly housed in aquariums. Their highly social nature also contributes to mass strandings, where large groups can become beached, possibly due to disorientation from underwater noise or following a distressed individual.
Safe Encounters and Conservation
When encountering false killer whales in their natural habitat, it is important to observe responsible wildlife viewing practices. Maintaining a respectful distance and avoiding any actions that might provoke them are recommended. Recognizing them as wild animals that deserve space and protection is paramount.
The global population of false killer whales is listed as “Near Threatened” by the IUCN, partly because comprehensive worldwide population estimates are not available. However, specific populations, such as the main Hawaiian Islands insular false killer whale distinct population segment, are listed as endangered under the Endangered Species Act, numbering fewer than 200 individuals. The primary threat to false killer whales is interaction with fisheries, through incidental bycatch, hooking, and entanglement. Other concerns include environmental contaminants and, in some regions like Japan, direct hunting. Efforts are underway to mitigate these threats, including measures to reduce fishery interactions and protect their designated habitats.