Ballenas y delfines de la Antártida: 12 cetáceos que puede ver

Antarctica is one of the finest destinations in the world for whale-watching. The immensely productive waters of the Southern Ocean, famous for their huge population of krill, draw both baleen and toothed whales to the bottom of the world. From pack-hunting orcas to the largest animal on Earth, the blue whale, these marine mammals rank among the most coveted sights for Antarctic cruise-goers.

In the following guide, we’ll run through the main species of Antarctic whales and serve up some insights into where and when to see them.

Baleen Whales in Antarctica

Baleen whales are distinguished by the baleen (“whalebone”) plates within their mouths that allow them to filter-feed. These include the largest of all whales, the blue and fin whales, and all of the so-called “great whales” besides the sperm whale.

Antarctica’s baleen whales, which are primarily summertime visitors migrating here to feast on abundant krill and other prey, include representatives of two families: the southern right whale of Family Balaenidae, as well as the rorquals, or “groove-throated” whales, of Family Balaenopteridae, which boast pleated underjaws and throats. Antarctic rorquals include the blue, fin, sei, and humpback.

Humpback Whales

The acrobatic, long-flippered humpback is the most familiar great whale to Antarctic sightseers. That’s partly because it’s the most numerous baleen species foraging in summer off the Antarctic Peninsula, and also because it frequently feeds close to shore—and puts on quite the show while doing it.

Humpbacks are rorquals that typically reach about 50 feet long and weigh up to 35 to 40 tons. They’re pretty easy to identify, what with their tapered knobby snouts and their elegantly long, whitish pectoral flippers, roughened at the leading edge by bumps called tubercles. The white underside of the humpback’s flukes, frequently raised vertically out of the water, set them apart from the darker tails of southern right or sperm whales. The “bushy” spout of the humpback whale is also distinctive.

A number of different stocks of Southern Hemisphere humpbacks summer in Antarctica, journeying here from low-latitude wintering/breeding grounds off West Africa, western Australia, the Galapagos, and other balmier climes. In their summertime polar playground, they feast on gargantuan amounts of Antarctic krill, throwing back several thousand pounds a day.

Humpbacks—which across their range also consume smallish schooling fish such as herring and anchovies—capture prey through a variety of methods. Like other rorquals, humpbacks engage in “lunge-feeding,” surging quickly with mouth agape into dense masses of krill. They’re also well known for “bubble-netting,” in which one or more whales circle up toward a school of prey, emitting ever-tightening screens of bubbles that panic and ball up the krill (or fish) near the surface; the humpbacks then engulf great mouthfuls.

Whether bubble-netting, flipper- or fluke-slapping, spyhopping, or all-out breaching, humpbacks—despite being slow swimmers compared to some of their fleet rorqual cousins—are highly active and visible at the surface: an unforgettable highlight of many an Antarctic Peninsula cruise.

Rorcual aliblanco antártico

This “lesser rorqual” is the second-smallest of its family and the third-smallest of the baleen whales, after its northern relative the common minke and the pygmy right whale. Still, compared to the global bestiary of life, this is still a big animal, adults reaching about 35 feet and 10 tons. The name “minke” apparently comes from a long-ago Norwegian called Meincke who, acting as spotter on a whaleship, mistook this animal for its bigger cousin, the blue whale.

Sleek and streamlined, with a sharp-pointed nose and a prominent, curved dorsal fin, the Antarctic minke is a lovely and swift creature, known for the “roostertail” wake that marks its passage at high speed. Although they will arch much of the upper part of their body out of the water—including their tailstock—in beginning a dive, minkes don’t raise their flukes above the surface.

The Antarctic minke whale often travels between lower latitudes in winter and polar waters in summer, but some individuals are known to overwinter in the Southern Ocean. Often seen in the Weddell, Ross, Davis, and other Antarctic seas, they commonly travel deep into the pack ice, following leads. Minkes feed mostly on Antarctic krill, though they sometimes take small fish as well. They, in turn, are commonly preyed on by orcas.

Antarctic minkes delight many a cruise vessel, given their notable tendency to approach boats out of seeming curiosity.

Ballena azul

The largest animal ever known to exist, the blue whale reaches its greatest size in Antarctica, where a unique subspecies—the (creatively named) Antarctic blue whale—exists. Antarctic blue whales average more than 80 feet in length and weigh more than 110 tons. Historical accounts speak of blue whales in Antarctica 100 to 110 feet long and weighing nearly 200 tons.

Essentially, the blue whale is mindbogglingly large. Heck, its tongue may weigh more than a bull African elephant, biggest of all land mammals!

These supersized rorquals are not just huge, but also rather gorgeous, with their namesake gray-blue, mottled hide (especially vibrant underwater), their great U-shaped heads (grooved-looking from above), and their graceful, streamlined form. That body plan makes blues, despite their gargantuan size, surprisingly speedy, capable of swimming at more than 20 miles per hour (32 km per hour). (Such swiftness, shared with close relatives such as the sei and finback, mean that these rorquals tend to be free of the barnacles that pepper the slower-swimming humpback, and are thus smoother-looking.)

In the cold polar waters, diatoms (an algae) often accumulate on the undersides of blue whales, giving them a yellowish hue. This explains the old whalers’ alternate name for this biggest of leviathans (one referenced by Melville in Moby-Dick): the “sulfur-bottom whale.”

In Antarctica, blue whales, like minkes, often penetrate deep into the pack ice. They almost exclusively eat krill, swallowing up (literally) tons of the crustaceans per day via lunge-feeding gulps. Such enormous daily intake of food is required to meet this titanic animal’s energy demands, and the great seasonal krill swarms off Antarctica explain why Southern Hemisphere blues—which likely winter in tropical offshore waters of the South Pacific, Atlantic, and Indian oceans—travel such distances annually to summer here.

Rorcual común

The fin whale, also known as the finback (and sometimes the “razorback”), is the second-largest of all whales after the blue; at maximum, it may reach lengths close to 80 feet and weigh more than 130 tons. It’s also a legendary speedster—the “greyhound of the seas,” according to naturalist/explorer Roy Chapman Andrews (although marginally outpaced by its smaller relative the sei whale), capable of cruising at 14 miles per hour (23 km per hour) or more, and exceeding 30 miles per hour (48 km per hour) in brief bursts.

Roughly resembling its slightly bigger cousin the blue whale, the fin has a narrower snout and a grayer hide free of the blue’s mottling. The undersides, including those of the flippers and flukes, are white.

Fin whales may eat two or three tons of krill and other food per day in Antarctica. They have a more varied diet than blues, targeting a variety of fish as well as plankton, and are deeper-diving than other rorquals. And they often gather in good-sized pods.

Given their great size, fins were prized alongside blue whales in the days of Antarctic whaling. The population here plummeted, but has lately shown encouraging signs of a rebound. Surveys in 2018 and 2019 documented some 100 groups of fin whales along the Antarctic Peninsula, including several pods numbering up to 150 individuals.

Rorcual boreal

The sei whale is probably the swiftest of all the rorquals, attaining speeds of 31 miles per hour (50 km per hour) or more. It’s the third-biggest, too, reaching lengths of about 53 feet (16m) and weights of 27 or so tons. The name (pronounced “say”) derives from the Norwegian seje, or “pollack,” a fish commonly associated with these whales in Norway’s waters.

Sei whales don’t tend to come as far south into Antarctic waters as the other rorquals, and indeed often summer north of the Antarctic Convergence. They’re commonly seen around South Georgia later in the summer and fall. But they’re still a potential sight in the Southern Ocean, where they tend to feed more heavily on copepods than the more krill-obsessed blues, fins, and humpbacks. Rather than employ lunge-feeding like those relatives, sei whales “skim” through schools of plankton.

Ballena franca austral

Like its Northern Hemisphere kin, the North Pacific and North Atlantic right whales, the southern right whale was heavily targeted by whalers; these were the “right” whales to target, on account of their slowness, bountiful blubber and baleen, and tendency to float rather than sink after being harpooned.

Reaching some 50 to 60 feet and about 80 to 100 tons, these are stocky baleen whales most notable for the thick knobs of skin (callosities) on their bulbous heads, patterned with barnacles and whale lice. Their V-shaped spouts allow for long-range identification.

Like the other great whales, southern right whales travel to higher latitudes in winter, though they don’t tend to come quite as deep into Antarctic waters as some of the rorquals.

Toothed Whales in Antarctica (Including Dolphins)

The toothed whales, or odontocetes, are the other suborder of living whales. As their name suggests, they’re differentiated from their baleen relatives by possessing (surprise, surprise) teeth.

The odontocete clan includes one great whale—the mighty sperm whale—and also the smaller cetaceans called dolphins and porpoises, plus such poorly understood families as the beaked whales.

Cachalote

Probably no whale is quite so iconic as the sperm whale, the kind most of us would sketch if asked to draw a whale and, of course, the namesake star of Moby-Dick. Reaching lengths of 60 feet or more and weighing more than 50 tons in the case of males (bulls), this is the biggest toothed predator on Earth and the only non-baleen member of the “great whale” guild.

Their gigantic heads, which may be a third of the total body length, contain massive spermaceti organs: source of the “sperm oil” so coveted by whalers. Their impressive teeth, which may be just shy of a foot long, stud only the narrow lower jaw.

Only adult bull sperm whales are known from Antarctic waters, migrating here for the summer on long journeys from tropical latitudes. This is a mirror image to the pattern in the Northern Hemisphere, where only bulls seem to regularly range into Arctic waters. While sperm whales show tight familial and social bonds in many parts of the world, these polar bulls tend to be solitary. In Antarctica, they range as far south as the edge of the ice pack.

While their fellow great whales are feasting on krill and copepods, sperm whales in Antarctica are making spectacularly deep dives after their favored prey: cephalopods. In the dark depths of the Southern Ocean, sperm whales are known to prey on such creatures as the giant and colossal squids as well as hooked squids and various other species. (In sub-Antarctic waters, sperm whales have also been documented feasting on Patagonian toothfish hooked on lines, and it’s possible that farther south they might hunt the very similar Antarctic toothfish.)

Orca (or Killer Whale)

Top predators of the World Ocean, orcas—commonly called killer whales, a corruption of the old whaler’s name for them, “whale killer”—are the biggest dolphins in the world. Strikingly patterned in black and white, the males possessing tall, spire-like dorsal fins, orcas are always arresting sights—and, to the many creatures they prey upon in the seas, likely terrifying sights.

Much scientific research in recent decades has suggested that orcas, including those of the Antarctic, are better thought of not as a single species or type but rather a collection of types or even subspecies. These varieties exhibit distinct morphologies and lifeways, and Antarctica has been at the forefront of distinguishing them.

Here, there appear to be at least three or four types (and maybe subspecies) of orcas. Type A orcas, the largest, show a “typical” killer-whale body plan and appear to particularly target minke whales as prey. Type B orcas, well known along the Antarctic Peninsula, include the pack-ice, or B1, orca, which seems to specialize in seals, and the Gerlache, or B2, orca, which hunts Weddell seals as well as penguins. Smaller yet is the Type C, or Ross Sea, orca, thought to mainly feed on Antarctic toothfish.

Another variety of killer whale, the Type D orca, frequents sub-Antarctic waters, but very little is known about it; marine biologists suspect it’s a fish-eater like the Type C orca.

Orcas get much of their imposing predatory prowess from their smarts and their cooperative hunting behavior. Banding together allows them to occasionally successfully prey on large baleen whales, though calves are more common targets. (Adult minke whales, which are not much bigger than a full-grown orca, are regularly taken.)

Seal-hunting orcas such as the pack-ice type use devilishly ingenious methods to catch prey: They will, for example, spyhop (sticking their heads well above water) to scan for basking seals on ice floes, then swim in unison to generate waves that break apart the floes or simply wash the seal into the water.

Delfín reloj de arena

The most southerly of all dolphins, the hourglass dolphin is one of the Antarctic’s most beautiful cetaceans, handsomely outfitted in black and white (the latter color patterned like an hourglass). That coloration also gives it the nicknames of “sea cow” (not to be confused with the sirenians—manatees and dugongs—often called sea cows) and “sea skunk.”

Very little is known about this smallish dolphin, which has a stubby beak and a large, hooked dorsal fin—a dead giveaway south of the Antarctic Convergence, where no other small toothed whale has that feature.

It’s an offshore species most commonly observed between about 45 degrees S and 65 degrees S, seemingly associated with the Convergence. Hourglass dolphins are often seen in the Drake Passage. Pods as large as 40 to 60 individuals have been documented. These dolphins frequently associate with other cetaceans—including fin and sei whales—and will ride the bow waves of ships.

Other Toothed Whales in Antarctica

En long-finned pilot whale, second-largest of the dolphins (males may exceed 20 feet and weigh several tons), is a common sight in sub-Antarctic waters and around the Antarctic Convergence, and sometimes strays farther south near the margin of the sea ice. This black, blunt-headed, pod-going toothed whale feeds mainly on squid.

A few other mysterious, poorly known toothed whales may range into Antarctic waters, including the Cuvier’s beaked whale y el southern bottlenose whale.

Caza de ballenas en la Antártida

The great numbers (and great size) of Southern Ocean cetaceans drew whalers down to the Antarctic in the 1800s. Whalers—and sealers, too—were at the forefront of Antarctic exploration, in fact, even as they quickly ravaged the stocks of baleen whales such as blues, fins, rights, and humpbacks.

You can read more about the history and legacy of Antarctic whaling aquí.

Whale-watching in Antarctica

As we’ve alluded to throughout, most whale action in Antarctica goes down in the summer—also, naturally, the peak of tourism here. Generally mid- to late summer are best for seeing whales. February is a particularly productive month, usually, with baleen whales well in evidence and orcas prowling the Antarctic Peninsula for young seals and penguins.