The Elusive False Killer Whale
In 2013, Jens Currie came to Pacific Whale Foundation as a data analyst from Canada’s Department of Fisheries and Oceans. With an ambition to explore more robust statistical methods of potential anthropogenic impacts on cetacean populations, Jens is now Senior Research Analyst. Here, he lends a helping hand for those of us that are new to understanding and appreciating the endangered false killer whale.
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What is a false killer whale, and can you dissect the name for me?
False killer whales are the fourth largest species of dolphin. They are characterized by their dark coloration, slender body, crescent-shaped dorsal fin, and small rounded head with no beak. Individuals of this species weigh between 1,000-3,000 lbs. Adult females reach lengths of 16 feet, while adult males are almost 20 feet long.
The name Pseudorca (pseudo-orca) comes from the similarly shaped skulls that false killer whales have to that of killer whales (Orcinus orca). The “crassidens” in their scientific name Pseudorca crassidens means “thick tooth.” They were first discovered and described by fossils.
What is their lifespan, what do they eat, how do they stand out?
These animals have a lifespan of 60 years or more. False killer whales feed primarily on fish and cephalopods in open water habitats. The prey items of this species include economically important fish, such as mahi-mahi and tuna, and occasionally other marine mammal species. It has been documented that false killer whales cooperatively hunt, and will share food between individuals in their group.
Where are they found in the world?
False killer whales are distributed throughout warm and temperate waters in the tropics and subtropics, with the highest abundance in warmer waters. They are typically found in the open ocean but can also occur closer to shore, particularly near tropical oceanic islands such as the Hawaiian Islands. Based on genetic and photographic data, there are three populations of false killer whales surrounding the Hawaiian Islands: the main Hawaiian Islands insular population, the northwestern Hawaiian Islands insular population, and an offshore/open-ocean population.
Do they migrate? Are they kama’aina?
They do not migrate and the main Hawaiian Islands insular population is kama’aina
Why are there so few remaining?
The endangered main Hawaiian Islands insular false killer whale population is estimated to be around 150 individuals. The historical population size is unknown; however, spotter planes from the 1980s report seeing large aggregations of 350-400 whales in a single area. Aerial data suggest that the population has declined at an average rate of 9% per year through the early 2000’s (NOAA Fisheries, 2018).
The reason why there are so few false killer whales is unknown; however, there are several factors that likely play a role. Given their endangered status, in 2010 a Biological Review Team (BRT) was established to conduct a status review of the species. In the Status Review report (Oleson et al. 2010) of the 29 identified threats identified, the most substantial threats to the population include: the effects of small population size (inbreeding depression and Allee effects), exposure to environmental contaminants, competition for food with commercial fisheries, and hooking, entanglement, and/or intentional harm by fishermen.
How can citizen scientists help us ID these elusive animals?
Citizen scientists can help us ID these animals by donating any photos they have of false killer whales in Hawaii. We can photo-identify individual Pseudorca through unique scars and markings, and by using their dorsal fin. Photo-identification is an important part of our research and how we can track changes in population size over time.
Another way to help is to notify PWF’s researchers when false killer whales are sighted in the Maui Nui region! We would greatly appreciate a phone call or text if any water users see false killer whales so we can initiate a rapid response (weather and time permitting).
Can you give me 3-5 reasons why they are awesome?
- They share food with each other, and have been documented offering fish to humans that are diving or boating.
- They are one of very few species known to enter menopause. Most animals continue to reproduce until they die; the only known exceptions to this are humans, killer whales, false killer whales, and short-finned pilot whales.
- False killer whales were first discovered by their fossils and were thought to be an extinct species until a pod was observed in 1861.
All photos and videos were taken under NMFS Permit # 16479.