Nothing…nothing…THERE!! A distant white smudge blurs a spot on the horizon: spray from a blue whale coming to surface. As our boat picks up speed in its direction, it comes in and out of sight as it too moves along. Now and then, crew members shout out which way to look: “one o’clock…ten o’clock” and so on.
Soon we can see portions of whale above the waves, then more and more whale as we close in. By and by, mysteriously, crew alert us that our whale is about to dive. How can they tell? Sure enough: up goes the broad tale, then down to disappear as dozens of onlookers emit simultaneous sighs of wonder: “haaah….” Minutes go by until another spout is sighted—THERE—“eleven o’clock”: some of us have joined the crew now in shouting out directions.
As an hour goes by of spouts, whales and tails, we learn that we are watching three blues repeatedly diving and surfacing. I wonder if our crew recognize any of them and whether they can tell male from female. Unfortunately, I forget to ask. I am fairly certain, however, that our massive friends are ‘lunge feeding’ on balls of krill: thumb-size, orange, shrimplike animals that congregate in their millions here and there at the edge of the continental shelf–offshore Sri Lanka’s south coast. I am hosted today by Mirissa Water Sports, an experienced pioneer in Lanka’s whale-watching sector. At our closest approach, one blue lies maybe 20 meters from the boat. Our excellent morning of blue sightings owes much to the fact that we are out in the November-December ‘high season’ while blues migrate from the Arabian Sea to the Bay of Bengal in search of good eats, which for blues means exclusively krill, krill and more krill.
Blue whales are not only the largest animals ever to live on our planet but possibly the largest that ever could. Their diet of proliferating krill affords them nutrition abundant enough to support their large size and high activity levels.
A typical blue feeding dive is an athletic marvel. Strokes from powerful tail flukes power her downward against her own buoyancy through the first 25 meters. As she descends, pressure from the water above forces her flexible rib cage inward, decreasing her volume and increasing her density so that her buoyancy dissipates and she begins to fall rapidly with gravity toward the sea bed. She turns and heaves herself upward in a strenuous ‘lunge’ through krill blooms, fighting not only gravity but also the huge hydrodynamic drag created by her own gaping jaws.
After a few seconds, she shudders to a halt, having gulped maybe sixty tons of seawater into her ventral pouch. With a gelatinous tongue the weight of an elephant, she spews the water out through her baleen—cartilaginous venetian-blind-like sieves that line her mouth instead of teeth—retaining thousands upon thousands of krill then to swallow. She does this all again and then again in a handful of successive lunges back toward the surface, holding her breath all the while of course. She floats gasping in the waves for several minutes before her tail goes up again in her next dive.
Along with the whales themselves, I catch glimpses of what could be a substantial threat to their well-being. The blues cruise along the edge of continental shelf extending under water several miles outward from Sri Lanka’s southern shore. Cold water ‘upwellings’ along the shelf edge carry organic nutrients toward the surface where photosynthesis utilizes them to produce blooms of plankton. Krill feed in turn on the plankton and grow numerous, thereby setting the table for blue whale lunches.
Ominously, however, the shelf edge is cruising territory not only for whales but also for huge, fast-moving ships taking the shortest route past Sri Lanka between the Bay of Bengal and the Arabian Sea.
Ships sometimes strike and kill the whales, as attested by several whale corpses observed in recent years. (One blue whale came all the way into Colombo harbor on the prow of the ship that killed it.) No one knows how many whales die this way.
Because blue whales typically sink when killed, there may be substantially more fatalities than we can observe. Out on the shelf edge, it is easy to visualize the collision course between ships and whales. Huge ships—an oil tanker out of Mumbai, a container ship called ‘Leopold Oldendorff ’ and so on—pass us no more than a kilometre away. A whale-watch boat—not one operated by Mirissa Water Sports— wanders too close to a tanker and gets reprimanded by a loud blast of fog horn.
After an hour of watching blues, we are in for another treat. A mile or so away, left of that group of boats: crew says orcas (killer whales) are there. We head off that way and soon pick them up: first two of those distinctive high dorsal fins, then three, then four, then five! They travel in tight formation, like jets flying wingtip-to-wingtip in an air show. That they are here while the blues cruise is likely no coincidence. Orcas predate on blues just as they do on many other seagoing mammals.
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. As of 2019, OPSL’s count of identified orcas in Lankan waters stood at 39, with perhaps six distinguishable pods. The pod we see is one associated with a female known as Raven.
Back in 2013, amateur whale-watchers near Mirissa caught footage of six orcas attacking a pod of five sperm whales. It represents the first recorded attack of orcas on sperm whales in the Indian Ocean, though such attacks have regularly been seen in the Pacific. In addition to this incident, OPSL has documented and analyzed two other apparent incidents of orca predation on whales in waters offshore Mirissa.
Later in 2013, observers spotted the orcas 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 preydown. They may snack heartily without killing their
prey outright.
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 kills amongst themselves after cooperating in complex coordinated hunting. Some orcas, for example, swim in synchronized 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. Or not: sometimes the orcas are just messing with the terrified seal. Orcas elsewhere herd evasive herring into tight balls where they can be smacked 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 whale and dolphin 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, which are terrified of orcas. Encountering orcas off the coast of California, one great white dove
deep and swam all the way to Hawaii before it slowed down. Orcas can grab a great white by the tail and flip it onto its back, sending it into a state of torpor known as ‘tonic immobility.’ They can then rip out and gorge themselves on its delicious fatty liver, which can weigh hundreds of pounds. Remarkably though, orcas in the wild never attack humans. This is probably not because they recognize us as high-IQ companions, fun as it might be to think so.
They may understand that we are dangerous to mess with. They may also view us as not snack-worthy: too many big bones and not enough fat and blubber. As I say, they tend to be fussy eaters. The whale-watch season in southern Lanka is just around the corner. Outfitters and crews are making preparations. They could use your business in this tourist-starved moment. Make a plan to get out there.