Orca Lanka: Killer whales are here and well worth meeting
You see splashing and thrashing but it’s hard to see exactly what’s going on. Half a dozen orcas (killer whales) off Lanka’s southern coast have launched a well-orchestrated attack on five sperm whales, one of them a young calf. Voices on the video indicate that the orcas are repeatedly lunging at the sperms and biting them. A still photo shot by one onlooker shows a sperm whale, its snout and jaw upside down above the waves, as it seems to shudder in pain, panic and exhaustion.
Voices on the video mention the smell of blood and exclaim that the orcas have separated the calf from its elders, which was undoubtedly their precise intention. After half an hour of frantic confrontation (not all of it captured on the video) some or all of the sperm whales, according to witnesses, manage to swim away in shoulder-to-shoulder formation as the orcas relinquish their attack. A strong oily smell indicates serious injury to at least one sperm whale.
The episode marks the first documented orca attack on sperm whales in the northern Indian Ocean. Orca predation on sperm whales occurs regularly in the Pacific Ocean but apparently not at all in the Atlantic. The Lankan attack conforms with behaviour patterns observed in the Pacific.
Sperm whales take up a wheel-spoke formation with juveniles and other vulnerables protected on the inside. In the Sri Lanka incident, they formed up with heads toward the centre and powerful tail flukes facing outward. Sometimes, however, they form up with tails toward the centre and formidable teeth facing outward.
Underwater footage from the Sri Lanka incident at one point shows three sperm whales lined up abreast with jaws agape and teeth exposed. Orcas attempt to disrupt these formations by lunges, butts, bites, flanking moves and squeezing between. They aim to terrorise, exhaust and separate. As with their other prey, they may try to hold a sperm whale underwater to drown it.
Sperm whales nearly always remain on the defensive, rather than going over to attack. Though capable of diving far deeper than orcas, they seldom appear to escape that way, perhaps because this could leave their calves exposed or because calves cannot sustain such deep diving.
With the rise of Sri Lanka’s whale-watching sector, it has become increasingly clear that orcas frequent our nearby seas. They have been spotted with some regularity off the south coast over the past few years, as well as off the west coast near Kalpitiya and on the east near Trincomalee.
A citizen-science initiative called the Orca Project of Sri Lanka (OPSL) uses photos to identify and count orcas in Lankan waters, and compiles reports and data on sightings and behaviours. It utilises information from “whale watchers, NGOs, researchers, fishermen, yachties, marine enthusiasts” and others.
OPSL’s count of identified orcas in Lankan waters now stands at 27, with perhaps six distinguishable pods. Some pod mates of identified individuals have not yet been confirmed as previously-sighted. OPSL contributes to a wider catalogue maintained by the Northern Indian Ocean Killer Whale Alliance, which compiles sightings from Indonesia all the way to the Arabian Peninsula. So far, its count of identified orcas stands at 51.
Contributors identify individual orcas by the size and shape of their white eye patches—no two animals are alike—and through idiosyncrasies like conspicuous injuries. Nicks, tears and scars in dorsal fins are especially valuable.
Two orcas, King and Arya, have been sighted together 17 times since 2008 and at all three Lankan hot spots: east, south and west. Though this could indicate that they actually reside here, OPSL co-founder Georgina Gemmell reserves judgment. She points out that orca sightings peak in the November-January and March-April periods when blue and sperm whales roam through Lankan waters.
In addition to the early-2013 sperm whale attack described above, OPSL has documented and analysed two other apparent incidents of orca predation on whales in waters offshore Mirissa. Later in 2013, observers spotted King and Arya swimming around with a beaked whale they seem to have just finished killing.
It appears to be the first-ever confirmed orca killing of beaked whales from that particular genus. In 2014, observers encountered a blue whale “thin and apparently unable to dive” with serious injuries characteristic of orca attack: extensive rake marks from teeth, gaping flesh wounds on flank and abdomen, flippers gashed with one tip missing, dorsal fin torn off.
Blues flee at high speed from attacking orcas, while orcas attempt to wound them into weakness. Orcas will bite and hold onto flippers, dorsal fins and tail flukes to slow their prey down. They may snack heartily without killing their prey outright.
Little is known about tropical orcas, as opposed to well-studied ones who inhabit chillier seas. Ms. Gemmell judges Lankan orcas to be on the skinny side, a clue perhaps to challenges they face in finding enough food. She conjectures that they forage widely and opportunistically, rather than specialising in one abundant prey food like many orcas elsewhere.
Two orcas spotted together here, Arion and Lassna, were sighted in 2008 off the coast of Abu Dhabi, 3,500 kilometers away. This huge range further suggests serious challenge in making a living.
Orcas have been lauded as earth’s most astonishing animals. One scientist suggests that they were ‘brainiacs’ of the planet for 10 million years or so before humans appeared 200 thousand years ago.
Such a view is difficult to assess of course, since orcas have no hands, use no tools (that we know of) and leave no artifacts. But they manifest a high degree of social learning and are described by some scientists as having heavily ‘cultural’ dimensions to their behaviours. They teach complex foraging strategies to their young.
They spend their lives in tight-knit pods embedded within defined clans and larger distinct communities. Pod members appear to communicate among themselves in ‘dialects’ varying from those of other pods living nearby. Pod members often share highly selective cuisine preferences. Some, for example, dine almost exclusively on a single species of salmon, though waters around them abound in many kinds of fish and other potential prey.
Orcas customarily share kill amongst themselves after cooperating in complex coordinated hunting. Some orcas, for example, swim in synchronised fashion toward a seal perched on an ice floe. This creates a wave that tips the floe and plunges the seal into the water where orcas dismember it.
Orcas elsewhere herd evasive herring into tight balls where they can be wacked by killer whale tails. Hugely adaptive, orcas range across all oceans. Their fearsome hunting may lie behind extinctions over the past 10 million years of several cetacean species, along with species of seals and their kin (pinnipeds) and sea cows.
Under normal circumstances, healthy orcas never fall prey to other animals, not even great white sharks. Try snatching that scrumptious-looking orca calf from his pod and see what happens to you. Even if you somehow manage to snag him, his aunties and cousins will kill you before you can eat. Remarkably though, orcas in the wild never attack humans. Is this because we don’t look tasty or because they recognise us as high-IQ companions?
Orcas practice ‘fads’ of play activity such as tossing dead salmon or toying with porpoises. A play fad originates with one or a few orcas, gets copied and popularised, then disappears as mysteriously as it arose.
Consider a working definition of ‘culture’ as a level of social learning in a species accounting for a high degree of its behaviour. Consider as well that ‘culture’ can be inferred when different groups within a species behave differently (e.g., some orca pods love eating salmon while others prefer seals) and this variation cannot be explained by divergent genes or environments.
By such criteria, a list of strongly ‘cultural’ animals might include several species of whale and dolphin along with apes and certain monkeys, elephants, meerkats, rats and a handful of birds and fishes. Social learning thrives where an animal’s environment falls in an intermediate zone of variability.
If the environment pertinent to an animal’s lifestyle rarely varies, social learning is not needed and will not evolve: genetically-driven instinct will do just fine. On the other hand, if an environment varies wildly—chaotically and without discernible patterns—social learning is impossible.
Social learning emerges when an environment varies in partially patterned fashion so that behavioural modifications within a given lifetime help an animal thrive. It requires life spans long enough for transmitting and retaining knowledge and skills. Orcas live as long as humans, maybe even longer.
It seems that the combination of marine environment and hunting lifestyle fosters social learning among animals prepared to utilise it. Several odontocete cetaceans (whales and dolphins with teeth) appear to fit this bill, especially bottlenose dolphins, sperm whales and orcas.
Some experts trace this success in social learning precisely to the fact that cetaceans are mammals. Having evolved originally on land, cetacean ancestors (cousins of today’s quasi-aquatic hippos) colonised the seas upon the mass extinction of dinosaur-ish marine reptiles which had previously occupied key niches.
They went to sea pre-equipped with tools favourable to social learning: lungs, large brains, good hearing, warm blood and strong social bonds radiating outward from the mother-child nursing relationship.
Mammalian features in a marine hunting lifestyle fostered a positive feedback loop for braininess and social learning. Breathing with lungs at the surface, while inconvenient, allows cetaceans access to air, which is 10 to 20 times more oxygen-rich than water.
High oxygen use facilitates warm blood, high activity levels and big brains. Single-calf births favoured mother-child bonding. The marine environment fostered heavy reliance on the sense of hearing, as sound travels better in water than in air, just as light does the opposite, rendering eyesight less valuable.
Good hearing and good vocalisation due to air-breathing structures fostered complex communication. Odontocetes used the sound-favouring properties of water to develop hearing into a virtual ‘sixth sense’—echolocation—broadly akin to that of bats.
By vocalising and hearing contours in the bounce-back, orcas and other odontocetes ‘see’ their surroundings with intricate detail through sound. It appears that echolocation may itself be a mode of communication, as individuals gain information not only from their own vocalisations and echoes but also from those of their pod mates. Echolocation may in fact be a kind of ‘group sense.’
Scientists who know them well speculate that orcas possess emotional nuance and problem-solving capacity rivalling our own. What might this say about how we should treat them and their habitat? Sri Lanka now confronts that question.
(From the archives: First published in Echelon Magazine in December 2016)