Whales and Dolphins You Can See on Your Antarctic Adventures

As you sail away from Ushuaia through the Beagle Channel and out into the Drake Passage, the dusky dolphin is one of the two dolphin species that you may see. These small dolphins, measuring up to 2.2 metres (seven feet), may follow the ship in pods of ten to twenty animals.

The dusky dolphin feeds on small fish, squid, and crustaceans. They are very acrobatic, porpoising with great splashes, and at times jumping clear out of the water. They also like to ride the ship’s bow wave.

The dusky dolphin has a bluish-black body covered with light grey and black streaks along the flanks and tail stalk. Its head has a band of light grey across the upper jaw. It lacks a distinct beak and has light grey flippers.

Duskies can be distinguished from the other common Beagle Channel dolphin (not shown here), the Peale’s dolphin, which has a black head and throat, a single light streak along the tail stalk, and darker flippers.

Once inside the Drake Passage, you are entering the domain of large whales. One common species is the fin whale, the second largest animal that ever lived, after the blue whale. Fin whales measure from seventeen to twenty-seven metres (fifty-six to eighty-nine feet) in the Southern Hemisphere.

They are recognised by their large size, their tall columnar blow reaching between four to eight metres (thirteen to twenty-six feet) high, and their prominent curved fin at the second third portion of the back. Fin whales are often very active at the surface, surfacing obliquely head first. Their large, hooked fin appears several seconds after the blow. They arch their back as they rapidly dive and rarely show their tail flukes.

Fin whales feed mostly on krill and other crustaceans in the Southern Ocean, but they also take schooling fish and squid. They engulf enormous schools of their prey in a single mouthful after expanding their highly flexible throat to capture them and the neighbouring seawater. They then retract their throat muscles to force the water out through the baleen, retaining the prey in their mouth before swallowing it. When seen from above, a gulping fin whale looks like a huge tadpole with its throat is fully distended.

The humpback whale is a common species of the Antarctic Peninsula and Southern Ocean. Its numbers have recovered from historical commercial hunting much better than other large whales. As a result, they are probably the most frequently seen baleen whale on expedition cruises to Antarctica.

They are an odd-looking whale with a rear hump, a knobby dorsal fin, and long, white pectoral fins that are about a third of the length of their body. Humpback whales almost always raise their tail flukes before a long dive, much to the joy any nearby observers.

Humpback whales feed on krill and small schooling fish. They are famous for their unique bubble-netting technique, where they blow bubbles in a circle below the school of prey. The rising and expanding bubbles create a sort of netted curtain around the school, causing it to tighten into a prey ball. The humpback then rises to the prey ball and engulfs it into its pelican-like expanding throat. The water is expelled through the baleen plates as the throat retracts, while the prey is retained in the mouth.

Humpback whales are not shy and will readily swim and feed near a flotilla of Zodiacs, or even near the expedition ship! Zodiac drivers and the captain are very careful to give them the space necessary when sailing.

Another conspicuous species along the Antarctic Peninsula and the subantarctic islands is the killer whale, also known as an orca. These large, toothed whales are top predator of these waters. There are four distinct ecotypes inhabiting the Southern Ocean. They are distinguished by the size, shape, and colour of their eye patch and by their feeding behaviour and prey selection.

The most commonly seen along the Antarctic Peninsula is the Type B, also referred to as pack ice killer whales, due to their habit of hunting seals on the pack ice. They do so by rushing the pack ice, creating an artificial wave meant to sweep the seals off the ice floes. The three other ecotypes are seldom seen; some are specialised in large whale hunting, while others go after deep fish prey.

Type B killer whales are highly social, forming pods of five to ten members, but sometimes grouping with other pods to form herds of up to fifty animals. They are easily recognised by the distinctive mid-back dorsal fin, which is tallest and straightest in males and shorter and slightly curved in females and young. Dorsal fins in some males can reach more than 1.5 metres (five feet). They have a large oval eye patch; that patch and their white saddle behind the dorsal fin often have a yellowish tinge.

The dwarf minke whale is a newly differentiated sub-species of the Antarctic minke whale, quite similar to the Atlantic and Pacific Minke whales. While the larger species shows an almost uniformly black body with a mid-back hooked dorsal fin, the smaller dwarf sub-species is distinguished by the mostly entirely white upper surface of its pectoral flippers and white band fading to grey along the flanks behind the flippers. Of course, those are not visible at sea from a distance, so the two species can be easily confused.

Both Antarctic and dwarf minke whales can be inquisitive and approach a Zodiac, even spy-hopping to get a good view, to the delight of passengers. Antarctic minke whales feed on krill, manoeuvring around schools of these small crustaceans to tighten them into a prey ball and engulf them into their expanding throats.

The water is then released through their short baleen plates, which acts as a sieve. Dwarf minke whales feed on schools of lanternfish and some krill, probably capturing them in much the same manner as the Antarctic minke.

These are only a few of the many species of whales and dolphins that inhabit the Southern Ocean and Antarctic waters. You are encouraged to spend as much time as you can on the ship’s decks or in Zodiacs looking for them and other cetaceans. Keep your eyes peeled and your binoculars and camera near you! Remember, the number one key to spotting wildlife is to be there and have your gear ready to use.