A Day With False Killer Whales

Posted by Jeffrey Milisen on Saturday, March 14, 2015

False killer whale coming in for a closer look at the boat.

Two weeks ago I woke up at 6 am to a dilemma.  On the one hand I was meeting my friend in an hour to try to find some hammerhead sharks from my boat.  Option “B” was a cryptic text message saying, “Jeff, call me if you are up.” Satellite tags deployed by Cascadia Research Collective on the back of a pod of endangered false killer whales (Pseudorca crassidens) showed that they were 14 miles south of the harbor and making their way up the Kona coast fast.  False killers belong to a visually similar group of dark colored marine mammals collectively known as “blackfish” and, as a result, are often overlooked by ocean users. My job was to photograph the individuals in the pod so identifications could be made regarding the complex social group.  Three days prior they were on Kauai and had already lapped the Big Island, a total journey of over 500 miles. Forty-five minutes after receiving the text, I had canceled the former plans and launching a boat to witness some of the most interesting mammals in the ocean.  
My connection with false killer whales starts with a seemingly unrelated species of megafauna.  Whale shark encounters in Hawaii are special in that A) they are enormous animals with no capacity to injure people B) they are exceedingly rare and C) the animals in Kona often become quite curious about the boats and swimmers. My coworkers on an offshore aquaculture project known as Velella spent an entire day with a whale shark that had become interested in the cage and equipment. That evening as the crew was eating dinner the shark became nervous and started hiding under the support vessel.  A pod of 4 false killer whales came in and began attacking the crew’s 20-foot-long pet, nipping at its fins and dragging it around the boat.  In a flash, the attackers had dragged the terrified shark 100 feet away and attempted to lift it out of the water.  The false killers were never observed eating the shark and no blood sheens were observed on the water’s surface.  It would seem they just wanted to have some fun.  The divers on the Velella project happily recall encounters with the oceans biggest and baddest, but after that day, none would enter the water when false killers were in the area.

A whale shark.  Just because.

Their legendary status goes beyond a single playful event on an obscure research project.  They move with a worrying aggressiveness unmatched by other sealife displaying a huge array of behaviors.  Think of aggressive dolphins on steroids.  They are odontocetes and thus have a larger brain to body-mass ratio than humans, with an especially enlarged communication center.  In a day of observation, one can expect to see complex social interactions, spyhopping, breeching, curious approaches to nearby boats, and strategic evasive maneuvers.  But by far the most exciting and important behaviors to watch are those associated with hunting.
The energy required to cover 500 miles in 3 days requires false killer whales to efficiently hunt while on the move in a variety of habitats from deep sea to epipelagic to coastal reef fishes.  At 15-20 feet long apiece, they are perfectly suited to hunt just about anything.  They typically spread 10-20 whales out over many miles to cover the most ground possible. When prey is found, the word gets out and 4-6 animals will suddenly appear together to share in the hunt.  Once the feast is over, the false killers will resume their places and continue on their way.  They are so efficient at hunting that they will often hunt more than they can consume just for the sport of it. Divers report that the sound of a false killer whale ripping a 50-pound ono in two is similar to the sound of separating Velcro.  

A mother and calf.

As animals go, false killer whales are as fascinating as they are in trouble.  Hawaii has three genetically distinct groups, pelagic, Main Hawaiian insular and the Northwestern Hawaiian Islands stock.  The Main Hawaiian insular stock to which this group of animals belongs is estimated at only 123 animals and is listed as Endangered under the Endangered Species Act.  The main threat to this stock is the presence of swordfish and tuna longline fisheries that between 2007 and 2011 took 25 false killer whales from the pelagic and insular populations. 
Six hours after launching we had covered 30 miles of ocean and witnessed two successful hunts in addition to various social displays and an unbelievable assortment of behaviors.  The photos, made from the surface and by hanging cameras over the side, will contribute to future studies.  Opportunities to interact, however distantly, with these intelligent, sentient ocean animals offer rare glimpses into the fascinating lives of one of the ocean’s most intelligent inhabitants.

Tags: false killer whale pseudorca crassidens 

Make a free website with Yola