Video: How can animals like orcas that breathe voluntarily sleep? It's a team thing


EndangeredSpecies Environment KillerWhales Orcas SalishSea SouthernResidentOrcas

We know that killer whales are unusually social animals. Even the way that orcas sleep is social, something shared. It’s something beautiful to behold.

I was still sipping my morning coffee one of the mornings at Kaikash Creek, a wilderness camp in British Columbia’s Johnstone Strait, when a pod of orcas, sleeping, came past. You could tell they were asleep because the procession—kooosh kooosh kooosh in succession as they broke the surface of the glasslike water, rhythmic and slow and majestic—was clustered together closely, in a line, and surfacing only every 45 seconds or so, coming up and going down as a group. I tossed my hydrophone in the water, then sat on my log and watched them through my camera. The only other sounds were the keening of the gulls that occupied much of the rocky beach.

Every breath that killer whales take is voluntary and conscious; unlike most land mammals, most cetaceans do not have an involuntary breathing mode. Early human captors discovered that when they anesthetized dolphins and orcas in their care, it killed them because they simply stopped breathing. Sleep, however, is a physiological requirement of every mammal on Earth. So, when and how do they manage it?

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In the case of killer whales (and most dolphins), the trick involves shutting down only half of their brain during a given sleeping session, remaining just awake enough to swim, surface, and breathe, all in a slow, rhythmic pattern. In the wild, where orcas swim almost constantly, this is done in large pods of up to 12 whales who line up in a wide arc and draft off each other’s wakes as they rise, breathe, and submerge together.

This is something spectacular to see, even if the orcas are not at all playful when sleeping. There is nothing quite as moving as the sight and sound of a long row of killer whales surfacing one after another, the plumes hanging in the air, and then vanishing below the surface when the procession finally reaches the end of the row. The silence follows, hanging there, for somewhere between 15 and 20 seconds, and then as certain as a clock, the first in line resurfaces again a little further along on the same line of travel, and the whole row rises behind them like fingers rising and falling on an oceanic piano, playing a syncopated melody.

The one constant in orcas’ lives is their togetherness; sleeping and awake, eating and playing, traveling and exploring, everything is done together. Every ecotype of killer whale has been observed engaging in a form of prey sharing. Resident killer whales share salmon they have caught with other whales; transients and Antarctic whales share seal kills; North Atlantic orcas team up to herd herring into balls; and even New Zealand whales who hunt rays on the sea floor often team up to hunt them and then share their meals with one another. Moreover, these are animals who mostly remain with their familial group for every day and moment of their lives.

Even more striking is the social dimension of dolphins’ and orcas’ faculties of perception, especially their echolocation. Later that day, I encountered a calf with its mother off Kaikash Creek that seemed to be listening in on the echolocation bullets from its mother that were striking my kayak. Scientists have found that dolphins, too, “eavesdrop” on the echolocation sounds made by their fellow pod members. Brain specialist Harry Jerison observes:

The “social cognition” that arises from this kind of richly shared experience of the world would even lead to a different sense of self than humans experience. Jerison argues: “The communal experience might actually change the boundaries of the self to include several individuals.” This clearly indicates that dolphins—and particularly killer whales, in whom we have observed the most highly developed acoustic skills as well as the most elaborate social and communicative structures in the delphinid family—have powerful emotional and empathic connections to each other that are integral to their own personal identities as beings in the world. Their togetherness defines them as individuals.

Socializing is wired into orcas evolutionarily at a level that dwarfs the comparatively loose social ties of humans. One of the logical consequences of this is that it requires an abundance of the quality that makes social life possible: empathy. By empathy, we mean not simply the ability to sense what other people and beings may be feeling, but to feel it ourselves and then to act accordingly, perhaps contrary to one’s immediate self-interest or desires. It is empathy that not only makes orcas most like humans, but perhaps makes them more than human. For modern humans, empathy is not a universally desirable trait since it reeks of vulnerability in an ever-competitive world. For killer whales, empathy is an evolutionary advantage.

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