In a startling revelation, researchers have uncovered a suspicious group of orcas approximately 300 kilometers west of Monterey Bay, California.
Comprising 49 individuals, this group stands out significantly from existing orca populations based on their morphology, activity patterns, and prey preferences, suggesting the emergence of a previously unnamed ecotype.
Unlike typical orca groups that primarily target fish or go for the liver of sharks, this particular assembly exhibits a distinct appetite, favoring the consumption of pinnipeds, dolphins, sea turtles, and notably, engaging in attacks on the largest of the cetaceans—the sperm whale.
Researchers have documented their hunting tactics, which are characterized by extreme violence, involving headbutting, tail slapping, and even tossing prey into the air for amusement.
A recent study led by the University of British Columbia has uncovered a new trend among killer whales. Researchers analyzed all killer whale sightings between 1997 and 2021. While going through these sightings, they identified nine encounters that stood out as notably different from previously known killer whale groups.
As we know, killer whales are social animals, living in matrilineal pods with distinct cultures and traditions passed down through generations. This suggests that different killer whale families exhibit variations not only in appearance and vocalizations but also in dietary preferences and hunting techniques.
Generally speaking, there are three types of killer whale family groups:
Residents: These whales have highly stable memberships and often stay with their mothers for life without venturing far. They inhabit specific regions and primarily feed on fish. Different resident groups may have different preferences, with some specializing in salmon while others prefer herring.
Transients: Characterized by smaller group sizes and lack of fixed territories, transients roam between different marine areas, mainly preying on marine mammals.
Offshores: These whales live in large groups in more distant offshore waters, primarily feeding on sharks.
Now, the newly discovered killer whale group exhibits dorsal fin and patterning similarities with multiple known groups. They mainly prey on minke whales, northern elephant seals, and sea turtles, often bearing scars from encounters with cookiecutter sharks.
The cigar shark, also known as the cookiecutter shark, is a small-sized shark with a disproportionately large bite. Once attached to its prey, such as a sperm whale, it can carve out a circular chunk of flesh roughly the size of its own mouth using its teeth. These sharks inhabit the deeper waters of the southern Pacific Ocean. Consequently, it is speculated that pods of sperm whales also reside in this region.
Researchers further indicate that the exact size of this group remains uncertain. Currently, only 49 individuals have been observed, suggesting there may be more yet to be discovered.
The showdown between 35 killer whales and 9 sperm whales - who's tougher?
Well, judging by size alone, killer whales are only about one-third the size of sperm whales. Killer whales typically measure 6-9 meters in length and weigh around 6,600 kilograms, whereas sperm whales can reach lengths of up to 18 meters and weigh over 50 tons.
Apart from their sheer size advantage, sperm whales are formidable predators themselves, being toothed whales known for their strong fighting abilities. They even prey on massive creatures like giant squids.
Normally, a creature of this size wouldn't be considered prey for killer whales. However, these particular killer whales seem to be a new breed, bolder and more ruthless than usual.
In 1997, this group of killer whales launched an attack on sperm whales about 130 kilometers off the coast of California. The killer whales, numbering 35, faced off against 9 sperm whales.
The killer whales formed groups of 4-5 individuals and launched successive attacks on the sperm whales.
The primary targets of killer whale pods are typically females and juveniles. To protect the juveniles, they employ a tactic known as the Margaret Defense, where adult whales encircle the young ones with their heads inward and tails outward, forming a protective ring resembling flower petals, with their powerful tails acting as the main defensive weapon.
However, despite this defensive formation, the orcas show no signs of backing down. Their objective is clear: target the juvenile whales. They start their assault from beneath the protective circle, randomly selecting targets and launching surprise attacks, making it difficult for the whales to defend themselves.
Orcas are also remarkably patient, attacking in rotating groups, leveraging their numerical advantage to exhaust their opponents. Eventually, after a chase of 3 kilometers, the orcas manage to kill one of the whales, forcing the rest to retreat with injuries.
This skirmish ends with the death of one whale and injuries to others, highlighting the effectiveness of orcas' tactics against juveniles or smaller-sized females. However, when faced with adult male whales, orcas show fear. The moment a male arrives to rescue the group, the orcas immediately retreat!
At present, there hasn't been any DNA testing done on this group. Scientists speculate that its members may come from different families. They suspect these orcas might have been "exiled" by their families, ended up coincidentally congregating as outcasts, and then seized upon a new territory. Each member has mastered hunting techniques from different families. After learning from each other, they gained the ability to hunt giant prey like grey whales. Their familial culture is likely defined by what they eat. Whether this group will thrive in the long term or dissolve quickly is unknown. What's certain is that, like any organism, orcas are evolving in response to their environment. So far, they seem to be adapting well, developing tactics like liver-squeezing on sharks and learning to hunt large prey like blue whales.
