Sub-zero temperatures, months of darkness and some of the strongest winds on Earth. How does life survive in this vast polar desert?
Despite the many challenges, Antarctica is teeming with life. It is home to billions of krill, millions of seals and more penguins than anywhere else on the planet.
Read on to learn about some of this wonderful wildlife, and their remarkable adaptations to a continent that is so cold and dry, some scientists compare it to the Moon.
When it comes to Antarctic wildlife, penguins often steal the show. Eight of the world’s 18 penguin species live in Antarctica and on subantarctic islands.
While these flightless seabirds can be a little ungainly on land, they are extraordinary swimmers. With streamlined bodies like torpedoes, they use their flippers like wings for propulsion in the water, and their feet (and sometimes tail) to steer their course.
Penguins feed at sea, coming ashore to breed, rest and replace all their feathers at once in an annual catastrophic moult. With their mathematically precise huddles and pebble-stealing antics, they have developed some truly remarkable ways of thriving in this harsh environment.
Let’s learn a bit about some of the different species we find in Antarctica.
Scientific name: Aptenodytes forsteri
Height: avg 1.1 – 1.3m (43-51in)
Weight: 22 to 45 kg (49 to 99 lb)
Average lifespan in the wild: 15-20 years
IUCN Red List status: Near threatened
The largest penguin species on the planet, emperor penguins live further south than any other penguin.
While most penguins migrate north for the winter, emperors head south to breed in colonies up to 200km (125 miles) from the coast. In these icy colonies, emperor penguins can withstand temperatures as low as – 50°C (- 58°F) with winds gusting up to 200km per hour (124mph).
They form dense huddles, which are so effective at creating warmth that penguins in the middle of these cosy formations can enjoy temperatures of up to 37C (100F), even in air temperatures that are well below freezing!
Emperor penguins feed mainly on fish, krill and squid, and their remarkable diving skills give them access to some of the coldest, richest waters on Earth. The deepest recorded dive by an emperor penguin was up to 565m (1850 ft) deep: deeper than any other bird. They can stay underwater for 20 minutes, but the average dive is closer to five minutes and around 100 to 200 metres (328 ft to 656 ft).
Although emperor penguins can’t fly, they can leap up to three metres. They do this by diving deep and filling their feathers with a cloak of bubbles, which helps them launch into the air and leap onto the ice!
Scientific name: Pygoscelis adeliae
Height: avg 46 to 71 cm (18 to 28 in)
Weight: 3.6 to 6.0 kg (7.9 to 13.2 lb)
Average lifespan in the wild: 10–20 years
IUCN Red List status: Near threatened
These delightful birds are the smallest penguin species in Antarctica. Known for their sleek black and white colouring that resembles a tuxedo, the distinctive white ring around their eyes is an important identifying feature.
Like emperor penguins, Adélies live and breed exclusively in the polar regions. In fact, they are the only two penguin species that live permanently in Antarctica! However Adélie penguins have more in common with gentoo and chinstrap penguins, both of which are members of the brush-tailed penguin family.
Adélie penguin colonies can be found on rocky outcrops across the Antarctic coastline, where they build nests from small stones. In addition to providing shelter for incubating eggs and young chicks, the pebbles can be offered up to an object of affection as part of a courting ritual, and Adélie males are well-known for their cheeky pebble-stealing antics.
Adélie penguins lay two eggs annually, which hatch in early summer (usually December/January). After about a month, Adélie chicks are ready to leave the security of their parents’ nest and strike out with other penguin chicks in rowdy groups called creches. After 2-3 months their downy plumage is replaced by adult feathers and they are ready for life at sea.
Adélie penguins eat some fish and squid, but they rely on krill for most of their diet. This dependence on krill makes them vulnerable to changes in ocean conditions. Across the rapidly warming Antarctic Peninsula, their numbers have dropped by 70-90% since 1982. Despite this, their numbers are increasing across Antarctica.
Scientific name: Pygoscelis papua
Height: avg 51 to 90 cm (20 to 35 in)
Weight: 4.5 kg – 8.5 kg (9.9 lb – 19 lb)
Average lifespan in the wild: 15–20 years
IUCN Red List status: Least concern
Gentoo penguins are the third-largest member of the penguin family, found across the Antarctic Peninsula and several subantarctic islands. Their distinctive orange beaks and peach-coloured feet provide a flash of colour against an otherwise stark landscape.
Like their brush-tailed cousins, the Adélies and chinstraps, they seek out ice-free patches for their colonies, building nests out of stones. They are often found congregating on low-lying, rocky beaches in groups of a few to a few thousand. They generally lay two eggs, sometimes three. Chicks are born in early summer (December/January), and within a month they congregate in creches with other chicks. In March, they begin testing the waters as they fledge and start foraging for their own food.
Gentoo penguins have a diverse diet of fish, squid and krill. This flexibility has made them resilient to changes in ocean temperatures and reduced sea ice cover. Although the population of Adélie penguins appears to be decreasing across the Antarctic Peninsula, gentoo penguins are expanding.
They can dive up to 200m (655 ft) and stay underwater for up to seven minutes, but their great strength is their speed. They are the fastest penguin on Earth, capable of swimming up to 36km/h (22 mph).
Scientific name: Pygoscelis Antarcticus
Height: avg 68–76 cm (27–30 in)
Weight: 3.2–5.3 kg (7.1–11.7 lb)
Average lifespan in the wild: 15–20 years
IUCN Red List status: Least concern
Found across the Antarctic Peninsula and several Antarctic and subantarctic islands, the plucky chinstraps are the most numerous penguins in Antarctica. In the remote South Sandwich Islands archipelago, there are enormous colonies of around 1.2 million breeding pairs, like the one featured in BBC’s Planet Earth II.
Their name is derived from the black line under their chin which, combined with their black cap-like head colouring, makes them look like they’re wearing a little helmet.
Chinstraps are among the more gymnastic of the brush-tailed penguins, often building their nests on exposed rocky bluffs with hazardous access routes! Like Adélie and gentoo penguins, they generally lay two eggs. Chicks are born in early summer (December/January), and join creches with other chicks within about a month. By March, they are ready to fledge and begin their life as an adult.
World travellers, chinstrap penguins are common from the Antarctic Peninsula to islands across the subantarctic, but have been spotted as far north as New Zealand!
Like all penguins, their main predators at sea are leopard seals. On land, predatory seabirds such as skuas, southern giant petrels and snowy sheathbills pose a threat, particularly to fluffy chicks.
Scientific name: Aptenodytes patagonicus
Height: avg 70 to 100 cm (28 to 39 in)
Weight: 9.3 to 18 kg (21 to 40 lb)
Average lifespan in the wild: ~26 years
IUCN Red List status: Least concern
Second in size only to the emperor, these stately birds live in bustling colonies on subantarctic islands north of Antarctica. Sometimes confused with emperor penguins due to their colourful plumage and orange cheeks, king penguins do not visit Antarctica, preferring the relatively temperate conditions a little further north, between 45° and 55°S.
King penguins are graceful swimmers, and can often be spotted from the ship porpoising (leaping) out of the water to breathe, pick up speed and evade predators. They feed primarily on fish and squid, and return to shore to breed in enormous colonies.
Some colonies in South Georgia are home to up to 150,000 breeding pairs. That’s over 300,000 boisterous, wing-flapping birds! Serially monogamous, king penguins find their partner in the crowd by listening out for their unique call amid the cacophony of thousands of trumpeting penguins.
King penguins have a unique 13-16 month breeding cycle, which means that they can have a maximum of one chick every two years, or two chicks every three years. They incubate their eggs on their feet, like emperor penguins.
From the crabeater seal that doesn’t eat crabs, to the Weddell seal that sings like a space invader, Antarctic seals are fascinating – and sometimes a little furry.
Protected under the Antarctic Treaty’s Convention for the Conservation of Antarctic Seals, these marine mammals are flourishing in the cool haven of the Southern Ocean. Let’s take a closer look at some of the most common seals in Antarctica.
Scientific name: Leptonychotes weddellii
Length: avg 2.5–3.5 m (8 ft 2 in–11 ft 6 in)
Weight: 400–600 kg (880–1,320 lb)
Average lifespan in the wild: 30 years
IUCN Red List status: Least concern
Weddell seals are the most southerly breeding mammal on Earth. They never venture too far from home, preferring to range within 50-100km (31mph – 62mph) of their haul-outs on the fast-ice surrounding Antarctica.
During the summer, Weddell seals roam around the sea ice to feed on small fish, crustaceans and other small marine life – sometimes even penguins! They haul out onto the ice to rest, moult and pup.
When the ocean congeals into sea ice, they carve holes in the surface using their sharp canines and incisors. They use these holes, often called breathing holes, to access the bountiful waters below.
Weddell seals are prodigious divers and navigators, diving up to 700m deep and staying underwater for up to 80 minutes, before finding their way back to their small breathing holes, even in the 24-hour darkness in the depth of winter.
This is a remarkable, but perilous system. It takes consistent maintenance to prevent these breathing holes from freezing over. Over time their teeth wear down, and they become unable to maintain their own breathing holes. This is thought to be a common cause of Weddell seal mortality.
Known for their remarkable call, the Weddell seal’s complex symphony of otherworldly chirps and chimes has been described by some as like a ‘sci-fi spaceship’ or the call of a distant alien civilisation!
Scientific name: Lobodon carcinophaga
Length: avg 2.3 m (7.5 ft)
Weight: 200 kg (440 lb)
Average lifespan in the wild: 20-40 years
IUCNRed List status: Least concern
With a circumpolar distribution and an estimated population as high as 15 million, crabeater seals are the most abundant seal species in the world.
They spend the majority of their lives around the pack-ice surrounding Antarctica, although vagrants have been spotted as far north as Australia. In 2016, a lone crabeater seal was spotted on Anglesea beach in Victoria!
Oddly enough, crabeater seals don’t eat crabs. Their name, which has confused many travellers, comes from the German word ‘krebs’, which means crabs, crayfish and crustaceans in general.
Crabeater seals eat more krill (Euphasia superba) than any other seal species on Earth. After taking in a mouthful of krill and seawater they use their specialised, lobed (lobodontine) teeth to strain out the water.
It’s always a delight to spot these sociable seals congregating in small groups on ice floes around the Antarctic Peninsula. They are most commonly spotted in groups of less than ten, but there have been reports of enormous groups of up to 1000 crabeaters hauling out on the ice to rest, moult and breed.
Scientific name: Hydrurga leptonyx
Length: avg 2.4–3.5 m (7.9–11.5 ft)
Weight: 200 – 600kg (440 – 1,320lb)
Average lifespan in the wild: 12-26 years
IUCN Red List status: Least concern
The second-largest of the Antarctic seals, leopard seals are solitary animals and formidable hunters. They have a broad diet which, unlike other Antarctic seals, includes other marine mammals.
Leopard seals are not picky eaters, and will happily dine on a variety of fish, squid, small crustaceans, penguins and even small seals. Highly effective predators, their sleek, serpent-like body moves stealthily through the water at speeds of up to 40km/h (25mph), and their powerful jaws clamp down firmly on their prey.
Despite their grisly reputation and penchant for feathered and furry prey, almost half of a leopard seals’ diet is made up of krill and small crustaceans. They consume these by filter-feeding through specially grooved teeth, much like the crabeater seal.
Female leopard seals are larger than their male counterparts, growing up to 3 metres (10 feet) and reaching weights of 590kg (1300lb).
Found along the coasts of Antarctica and subantarctic islands, in 2017 they were spotted on beaches around Tasmania.
Scientific name: Mirounga leonina
Length:
Female 2.6 to 3 m (8.5 to 9.8 ft)
Male 4.2 to 5.8 m (14 to 19 ft)
Weight:
Female 400 to 900 kg (880 to 1,980 lb)
Male 2,200 to 4,000 kg (4,900 to 8,800 lb)
Average lifespan in the wild: 21 years
IUCN Red List status: Least concern
The giants of the Antarctic seals, southern elephant seals are the largest seals on the planet, and the largest mammals on Earth, apart from whales. However, they earn their name not from their size but from the long, trunk-like snouts sported by adult males.
Foraging widely across the Southern Ocean, southern elephant seals breed in densely packed colonies on subantarctic islands.
Dominant males surround themselves with a harem of 40 to 50 females, which they fiercely defend against hopeful interlopers. Violent clashes are a common sight on South Georgia’s beaches during mating season, with males battling for supremacy in aggressive, sometimes grisly matches.
Elephant seals often bunch together in muddy pits called wallows, using their small flippers to cover themselves with cool, wet sand.
Once hunted to near-extinction for the rich oil rendered from their blubber, elephant seal populations have rebounded well under strong protections in recent decades.
During the Antarctic summer, these leviathans of the deep flock to Antarctic waters in astonishing numbers to feast on the veritable bounty of Antarctic krill (Euphasia superba) that flourishes amidst the sea ice.
They generally begin to arrive in Antarctica in November, reaching peak numbers in February and March. Let’s take a look at some of the whales we see in Antarctica.
Scientific name: Megaptera novaeangliae
Length:
Female avg 15–16 m (49–52 ft)
Male avg 13–14 m (43–46 ft)
Weight: avg 25–30 metric tons (28–33 short tons)
Average lifespan in the wild: 45-50 years
IUCN Red List status: Least concern
These majestic giants are among the great wanderers of the sea, travelling up to 10,000km (6,200 miles) on their annual migration from their breeding grounds in the north to their feeding grounds in the south. This is the longest known annual migration of any mammal (although some say the gray whale migration may be further).
Humpback whales travel in pods, feeding on small fish, crustaceans and the abundant krill found in the nutrient-rich waters of the Southern Ocean. They use co-operative hunting techniques such as bubble-net feeding to corral huge swarms of Antarctic krill into a small area, before sweeping the thick soup of krill and water into their enormous, pleated gullet. They filter the water out using their huge baleen plates, made of a fibrous material a bit like our fingernails. Then they swallow a hearty mouthful of krill.
They are somewhat stout and stocky compared to other baleen whales, and travel comparatively slower. Females generally grow larger than males, as with all baleen whale species.
Humpback whales are quite curious, and expeditioners to Antarctica may be treated to wonderful displays of tail-slapping, pectoral fin-waving, breaching (leaping out of the water) or even humpback whales swimming towards the ship for a closer look.
Scientific name: Balaenoptera bonaerensis
Length:
Female avg 8 m (26 ft)
Male avg 6.9 m (23 ft)
Weight: avg 4–5 t (3.9–4.9 long tons; 4.4–5.5 short tons)
Average lifespan in the wild: 30-50 years
IUCN Red List status: Near threatened
The minke whale is one of the smallest baleen whales. Instead of teeth, baleen whales have curtains of flexible plates in their mouths, called baleen. Baleen plates are made of a material similar to the keratin in our hair and fingernails, and whales can have hundreds of them hanging from their upper jaw. Baleen is like a colander, allowing whales to filter-feed vast quantities of krill and small fish.
Inquisitive but shy, minke whales can be spotted by watchful travellers as they cautiously approach vessels, before darting away or diving quickly, not to resurface for several minutes.
Hunted by Japanese whaling ships until 2019, the minke whale population is currently classified as near threatened.
Scientific name: Orcinus orca
Length: avg 23 to 32 feet
Weight: Up to 6 tons
Average lifespan in the wild: 50 to 80 years
IUCN Red List status: Unknown (Data Deficient)
Although they are classed as toothed whales, killer whales are technically part of the dolphin family. They are the largest of the dolphins, and one of the world’s most formidable apex predators. They feed on fish, seals and even other whales.
Known for their extraordinary intelligence, killer whales hunt in pods of up to 40 individuals. They use echo-location to communicate, and employ cooperative hunting techniques, which some scientists compare to wolves. Watchful visitors to Antarctic waters may see them surfacing in the gaps amongst the sea ice, or circling around icebergs strategising a seal capture.
There are three types of killer whales in Antarctica:
Type A: the largest of the Antarctic killer whales, they prefer open water and feed mainly on minke whales.
Type B: these prefer the pack ice, feeding predominantly on Weddell seals, and also possibly penguins. They have a distinctive yellowish colouring on their white patches due to staining from diatoms in the water.
Type C: the smallest Antarctic killer whale, they are typically spotted amongst the pack ice in East Antarctica and are thought to eat mainly fish. Like Type B’s, they have a distinctive yellowish colouring.
Scientific name: Balaenoptera musculus
Length:
Female: avg 27m (88 ft)
Male: avg 25m (82 ft)
Longest blue whale ever: 33.58m (110ft 17in) measured at a South Georgia whaling station in the South Atlantic (1909) (Source)
Weight:
Female: 130 tons (260,000 lb)
Male: 112 tons (224,000 lb)
Average lifespan in the wild: 80-90 years
IUCN Red List status: Endangered
The blue whale is the largest mammal ever known to have lived on Earth. A quick online search will reveal the extraordinary scale of these colossal majesties of the deep.
A blue whale’s tongue can weigh as much as an elephant. Its heart is the size of a golf buggy, as heavy as a small car, and you can hear it beat from 5km (2 mi) away. Their call is among the loudest on Earth, with scientists estimating other whales can hear their calls 1,600km (1,000mi) away.
This extraordinary creature feeds exclusively on krill, consuming up to 4 tons of these tiny crustaceans each day. Usually travelling alone or in pairs, they are generally solitary animals.
Since being hunted to near extinction in the 18th and 19th centuries, blue whale populations appear to be rebounding. In February 2020, a group of scientists reported ‘astonishing’ numbers of blue whales off the coast of South Georgia, where they were once abundant and hunted in large numbers. In 23 days their survey counted an extraordinary 55 blue whales. While blue whales are still classified as endangered, scientists consider this return to their pre-whaling feeding grounds a very good sign.
In August 2020, a blue whale was seen off the coast of Sydney, Australia, in what is thought to be only the third local sighting in 100 years.
Length: avg 6cm (2.5 in)
Weight: 2g (0.7 oz)
Scientific name: Euphasia superba
Average lifespan in the wild: 10 years
Antarctic krill (Euphasia superba) are small crustaceans with large, black eyes and many small legs called thoracopods. They feed primarily on phytoplankton, and are found in large numbers across the Southern Ocean.
Krill tend to migrate vertically in the water column, rising to the surface and providing food for predators at night, and sinking into the depths during the day.
There are an estimated 500 trillion Antarctic krill in the Southern Ocean, weighing 379 million tons. Scientists estimate that approximately half of this is taken up by the seals, penguins and whales that rely on krill as their main source of food.
Antarctic krill is also commercially harvested by humans, mostly in the Scotia Sea, to the north of the Antarctic Peninsula. The main uses of harvested krill are aquaculture and aquarium feed, human dietary supplements and bait in sport fishing. Antarctic krill fisheries are regulated and monitored by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR).
The most endangered animals in Antarctica are albatrosses. As these majestic seabirds soar across the globe they fall prey to oil spills and entanglement in plastic or netting. They are also affected by changes in food concentration, loss of habitat and climate change.
The wandering and southern royal are the largest albatrosses, and two of the most common ones we see on our voyages. They are both classified by the IUCN Red List as vulnerable to becoming endangered, and wandering albatross numbers are listed as decreasing.
Of the 8 penguin species found in Antarctica, two are vulnerable, two are near-threatened and the others have healthy populations.
You can read more about Antarctic penguin populations here.
Antarctic seals and whales were hunted to near-extinction in the 18th and 19th centuries. While commercial sealing officially ended in 1972, commercial whaling continued in some form until 2019.
Today, humpback whales are thriving and they are listed as least concern. However many of the other large baleen whales, including the blue, fin and sei whales, have been slower to recover.
Blue and sei whales are both endangered, although their populations are increasing. There is good news for fin whales, which have been downgraded from endangered to vulnerable since 1999, and are increasing.
Despite having been hunted to within an inch of extinction, both fur seals and elephant seals have strong populations, crowding subantarctic beaches during breeding season and filling the air with their belches and battle cries. In fact, all Antarctic seals are faring well, classified as least concern.
You can read more about seal populations here.
Due to Antarctica’s inaccessibility and challenging research conditions, there are many species scientists still know very little about. There may be others we have yet to discover. As the ocean warms and the air temperature increases, the race is on to gather as much baseline data about Antarctic wildlife as possible.
Winter in Antarctica means six months of darkness and temperatures plummeting below -60°C (-76°F). While humans might put on a warm down jacket and a head-torch to survive, Antarctic animals take a different approach. They have developed all kinds of handy adaptations to help them thrive in a climate that can seem impossibly harsh.
The Antarctic continent itself is barren, windswept and covered in ice. By contrast, the ocean surrounding it is teeming with life.
All Antarctic animals (with the exception of tiny invertebrates and one scavenging bird, the snowy sheathbill) spend most of their lives feeding in the nutrient-rich waters surrounding the continent. Underwater, they are protected from the extremes of the Antarctic environment, and many migrate north for the winter.
Antarctic penguins and seals only haul out on land or ice to breed, raise their pups or chicks, rest and moult (replace their old feathers or skin with a fresh new cover).
Antarctic seals have large eyes to help them hunt under ice and in low light which can endure for up to 6 months. Some Ross seal eyes are 7cm (2.75 in) in diameter!
Seals also have whiskers (vibrissae), which are like little antennae that help them home in on their prey, even with their eyes and ears shut! These highly sensitive hairs can detect the movement of tiny prey in the water at a greater distance than seals can see or hear.
Scientists aren’t sure how penguins hunt in the dark, but they suspect that bioluminescence in some squids, crustaceans, and fish could help guide them.
Penguins and seals keep themselves warm with layers of blubber (fat). Most Antarctic seals rely entirely on these thick layers of blubber to keep them warm. Fur seals, however, take a different approach, sporting some of the warmest fur around. Their highly efficient fur is made up of two parts: dense, water-resistant and insulating underfur – up to 300,000 hairs per square inch on a fur seal – and coarse guard hairs, which are longer and protect the underfur from water and abrasion.
Penguins, like fur seals, don’t rely entirely on blubber to keep them warm. In addition to blubber, they have four different types of feathers, with an outer layer of ‘contour feathers’ that acts as a waterproof shield, protecting the insulating, downy layers inside.
Emperor penguins are the only penguin species that breeds in Antarctica during the winter. They form large huddles, each penguin taking its place with mathematical precision to maximise warmth in the middle of the huddle. They take turns being exposed to the cold on the outside, gradually moving towards the toasty middle, where temperatures can be up to 37C (100F), before beginning the process again.
The Antarctic Blackfin icefish has anti-freeze proteins in its blood to stop it from freezing, even if the water temperature drops below 0C (32F)!
A warming Antarctica will have a profound impact on the animals living there. While some species may migrate or even benefit from the changes, at least in the short term, others will struggle to adapt. Scientific research is helping us understand how a warming Antarctica could affect this complex ecosystem.
In 2019, scientists from the British Antarctic Survey released an update on the impacts of Antarctic melting on wildlife. They reported that so far we are on track for a ‘few winners many losers’ scenario. While some species will benefit from the melt as it opens up new habitats, both on land and the seafloor, they won’t offset the losses as other species are pushed to the limit trying to survive.
According to their study, which was published in Frontiers in Marine Science, Antarctic krill and the penguins that rely on them are among the most at risk as the ice melts. Adélie and emperor penguins, Antarctica’s only permanent penguin residents, are particularly vulnerable.
But there is hope.
Scientists have identified possible ‘climate refugia’: little ecological pockets that could offer an icy safe haven to climate migrants in a warming Antarctica. In the past, the Ross and Amundsen Seas acted as glacial refuges on a warming Earth, and models suggest they could offer similar shelter in the future. The establishment of the Ross Sea Marine Protected Area in 2017 is a step towards the protection of these vital habitats as Antarctica warms.
Words by Nina Gallo, Aurora Expeditions’ historian and certified PTGA polar guide.
Nina has been drawn to the polar regions since her first otherworldly experience of the midnight sun in 2002. Since then she has spent time in far northern Canada, the Himalayas, the Alps and deserts in America and Australia, always seeking out quiet, wild corners to explore. She feels immensely privileged to travel to these places and shares her passions for the natural world, human stories and adventure with all the wonderful people she meets. Nina is the author of Antarctica, published by Australian Geographic in September 2020.
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