Over the course of this lecture, John talked about some of the organisms found in Antarctica that are often overlooked, given everyone’s fascination with penguins, seals, and whales.

He started off by talking about lichens. While they aren’t quite microscopic, he explained that they are composite organisms made up of multiple microscopic components living in a symbiotic relationship. The fungal component provides structure and protection, while algae or cyanobacteria live within it, supplying nutrients through photosynthesis and, in some cases, nitrogen fixation. Lichens come in a wide variety of shapes, sizes, and colours, with at least nine recognised growth forms, the most common being:

• • • Fruticose: Three-dimensional and bushy, with many branching structures
    • Foliose: Flat and leaf-like, with lobes that extend from a central attachment point
    • Crustose: Thin, flat, and tightly adhered to the underlying substrate

After this, John went on to list a variety of other life forms that had us all in awe, including:

• • • Arthropods: These include mites, which possess antifreeze compounds in their tissues and are largely herbivorous, feeding on mosses and lichens; midges, which are the only true insects native to Antarctica, are flightless, can survive year-round, and have adult lifespans of only a few days; and springtails, which can survive extreme desiccation and remain dormant for years.

    • Nematodes: Found primarily in the Antarctic dry valleys, these microscopic worms play a crucial role in soil nutrient cycling and ecosystem functioning.

    • Rotifers: Aquatic microinvertebrates found in freshwater and marine environments, often present in large numbers and capable of surviving desiccation by entering a dormant state.

    • Ctenophores: Almost exclusively marine organisms with eight rows of ciliated, often bioluminescent structures. Their populations are increasing in some regions due to rising water temperatures and ocean acidification.

    • Tardigrades: Also known as water bears, these extremophiles can survive near-freezing and near-boiling temperatures, ionising radiation, extreme pressure, and even the vacuum of space. They can also persist without food or water for up to a decade by entering cryptobiosis. Cool, cool.

    • Others: Sea angels, arrow worms, salps, and isopods, many of which play key roles in Antarctic marine food webs.

One particularly striking point John made was that much of Antarctic life exists at the edge of survivability. These organisms are not just cold-tolerant, they are cold-dependent. Their enzymes, membranes, and life cycles are finely tuned to stable, low temperatures, meaning that even slight warming can disrupt their physiology and ecological balance. In a place with so little redundancy, the loss of even the smallest organisms can have disproportionate consequences.

Whilst most people visit Antarctica to feast their eyes on penguins and whales, Heidi assured us that none of that would be possible without krill – a keystone species in the Antarctic ecosystem. Euphausia superba is the krill species found here, particularly concentrated around the Antarctic Convergence.

These four-to-six-centimetre, shrimp-like crustaceans are bug-eyed creatures with strong swimming legs and a specialised feeding basket they use to graze on phytoplankton and algae, sustaining their pelagic lifestyle. Although mostly transparent, they have red pigment spots scattered across their bodies, and their gastrointestinal tract is visible from the outside. They are usually found in enormous schools called swarms, which can contain anywhere between 10,000 and 30,000 krill per cubic metre. With an estimated total biomass of around 500 million metric tonnes, calculated using echo-sounders, krill outweigh the entire human population by roughly five times.

Krill swarms are often considered super-organisms, moving and behaving as a single coordinated unit. Interestingly, most individuals within these swarms are female, as females migrate offshore to spawn while males tend to remain closer to the coast. Krill are also bioluminescent, emitting light from specialised organs to help maintain swarm cohesion in the dark depths. Ironically, the same mechanism that helps protect them also makes them highly visible to predators. Tragic for the krill, sure – but also the very reason Antarctic marine life can thrive.

Their life cycle in the Southern Ocean begins in summer, when females release up to 10,000 eggs, each roughly half a millimetre in size. These eggs sink rapidly to depths of around 2.5 kilometres, where they are relatively safe from predators. After hatching, the larvae begin their slow ascent back toward the surface, feeding along the way on algae and phytoplankton, with sea-ice algae being particularly crucial for survival. Krill undergo multiple developmental stages, from nauplius larvae through several metamorphic phases, eventually becoming adults after a few months. During winter or periods of food scarcity, krill can shrink in size after moulting, reducing their metabolic demands and conserving energy until conditions improve. They can live for up to seven years, which is remarkably long for such small creatures.

Although cetaceans and seals consume vast quantities of krill – including the three tonnes per day eaten by a single blue whale – these predators are not the main drivers of krill population decline. Even that level of consumption pales in comparison to the impacts caused by humans. Climate change is the first major threat, driving ocean acidification and reducing the extent and duration of pack ice, which directly affects the growth of ice algae. This is particularly concerning in West Antarctica, where warming has been especially rapid. Less ice means less algae, and less algae means fewer krill.

The second major threat comes from fisheries. Despite tasting pretty awful due to their high fluoride content, humans have still found ways to exploit krill. Using large trawl nets, which can also trap non-target species, or vacuum-based harvesting systems, enormous quantities of krill are removed from the ocean. These are then frozen into slabs and processed into krill oil for human consumption, or used as bait and feed for aquaculture and livestock. In Antarctica, this is not a hypothetical problem – it’s a very real and ongoing one.

Krill fishing was entirely unregulated until 1982, when the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) established catch limits, setting a global precautionary quota of 8.6 million tonnes per year. Following this, krill fishing initially declined, largely coinciding with geopolitical tensions surrounding the Falkland Islands and conflicts involving the UK and Argentina. However, after 2010, krill harvesting began to rise again. Heidi even recounted an incident from 2016, when the ship she was working on encountered six illegal krill fishing vessels operating in the Gerlache Strait during a single expedition.

One additional point Heidi stressed was that Antarctic food webs have very little redundancy. There is no true substitute for krill. If krill populations collapse, there is no alternative species ready to step in and fill that ecological role. Penguins, seals, whales, fish, and seabirds would all feel the effects rapidly, making krill one of the most critical bottlenecks in the entire Southern Ocean ecosystem.

So yeah, if climate change and poverty and racism and forest fires and avian flu weren’t already enough to worry about, we can go ahead and add krill collapse to the ever-growing list of things we’re collectively screwing up.

During this presentation, Heidi introduced us to the species of birds we were most likely to encounter and their habits in Antarctica, with the fact that they have adapted to such harsh conditions being nothing short of amazing.

She continued building on Keith’s lecture, explaining that at the zone of convergence, nutrient-rich upwellings provide ideal feeding grounds for foraging seabirds and cetaceans. As a result, although most seabirds nest on islands around the continent, they range widely at sea and are often encountered far from land. Many seabirds, especially albatrosses, are particularly abundant between 40° and 65° south, where uninterrupted winds circulate vigorously around the globe. These latitudes, known as the roaring forties, furious fifties, and shrieking sixties, provide perfect conditions for ocean wanderers that can be encountered virtually anywhere in the vast Southern Ocean. As such, a species nesting on a tiny, remote subantarctic island near New Zealand may routinely forage off the coasts of South America or Africa.

Whilst seabirds possess numerous adaptations for life at sea, including unihemispherical sleep that allows them to fly for prolonged periods, preen glands that waterproof their feathers, and salt glands that function as desalination filters, those living south of the Antarctic Circumpolar Current had to take things up a notch. The dramatic drop in temperature, extreme winds, and seasonal darkness demand even greater physiological and behavioural specialisation.

Although there are six orders of seabirds, we would only be discussing a handful that we were likely to see on our trip:

• • Procellariiformes: Also known as tubenoses, these are pelagic birds with a near-global distribution. They tend to be monogamous and highly faithful to their nesting colonies. One of their defining features is a tubular nasal passage, which enhances their sense of smell, allowing them to detect dimethyl sulfide released by phytoplankton blooms and locate prey across vast distances. Families include:

    • • Diomedeidae: The albatrosses, among the largest flying birds on Earth, use dynamic and slope soaring to cover enormous distances with minimal effort.

        • • Wandering albatross: Holds the record for the largest wingspan of any living bird, reaching up to 3.5 metres. These birds can circumnavigate the Southern Ocean multiple times and are among the most wide-ranging animals on the planet. They have black and white wings, black-tipped tails, and a white body with a subtle pink flush on the cheeks. After hatching, they spend several years at sea before returning to breed, often not reaching sexual maturity until around ten years of age. They are exceptionally long-lived, with the oldest known individual, Wisdom, documented at over 70 years old and still breeding at the time of writing. Despite their elegance in flight, they are comically clumsy on land, with Heidi recounting one individual that needed 21 attempts to land before finally crash-landing in spectacular fashion.

          • Royal albatross: Slightly smaller than the wandering albatross, with a white tail and a black-lined bill.

          • Black-browed albatross: The most common albatross species, recognised by a gleaming white head, dark eyebrow-like markings, and black wings.

          • Grey-headed albatross: Closely related to the black-browed albatross but with a grey head, an orange-and-black beak, and a different breeding cycle.

          • Light-mantled albatross: Characterised by a coal-grey face with a white half-moon marking around the eyes. These birds are usually solitary at sea and are known for elegant courtship flights during the breeding season.

• • • • Procellariidae: This family includes fulmars, prions, shearwaters, gadfly petrels, and other petrels. Antarctic and snow petrels are among the southernmost breeding birds on Earth.

        • • Giant petrels: Nearly as large as albatrosses, these birds often feed on land and act as scavengers. A rare white morph exists, which Heidi noted with particular excitement.

          • Cape petrel: Also known as the pintado bird, easily recognised by its striking black-and-white speckled plumage.

          • Southern fulmar: Identified by a white face, grey body, and black tail with a white underside. They breed in Antarctica and migrate northward during winter.

          • Prions: Smaller, fast-flying birds with blue-grey plumage that skim low over the sea surface.

• • • • Oceanitidae: Storm petrels are the smallest seabirds in the world and can fit comfortably in the palm of one’s hand. Often referred to as Jesus Christ birds, they hover over the water and patter their feet on the surface to stir up krill and fish. Their bills have fine hook-like projections that help them grasp slippery prey, which they sometimes scavenge from the remains of seal or whale kills.

• • Sphenisciformes: Despite the intimidating name, this is the order that includes the most beloved birds of the Antarctic, penguins. Penguins first appeared around 50 to 60 million years ago, evolving from flying ancestors into highly specialised, flightless divers. Today, there are around 18 recognised species. 

These countershaded black-and-white birds are superbly adapted for life in the water and notoriously clumsy on land. Their wings have evolved into powerful flippers, and unlike most birds, their bones are solid rather than hollow, reducing buoyancy and improving diving efficiency. This is counterbalanced by a layer of blubber and streamlined body shape. Penguins also exhibit regional heterothermy through counter-current heat exchange, allowing them to conserve heat in cold waters. A thin layer of air trapped within their waterproof feathers adds further insulation. When overheated, usually at temperatures above 10 degrees Celsius, penguins flush and pant to cool down. Their signature waddle is partly due to knees hidden beneath feathers, which limits joint flexibility.

Armed with backward-facing, fishhook-like spines on their tongues and bills, penguins primarily feed on krill, one of the most abundant animals on Earth. The red pigment in krill passes through their digestive systems unchanged, giving penguin guano its characteristic pinkish hue. Because colonies are dense, noisy, and often coated in acidic guano, penguins spend a significant amount of time preening to protect their feathers.

Among the penguin species we were most likely to encounter on the Antarctic Peninsula are the brush-tailed penguins, named for their stiff, pencil-like tail feathers that help support them upright. Heidi explained that our first glimpse of them would probably be from the water, porpoising at speeds of up to 10 knots as they surfaced for air. These include:

• • • • Gentoo penguins: Recognised by their black backs, white undersides, white eye patches, and bright orange bills. They are the fastest-swimming penguins, capable of bursts of up to 36 kilometres per hour.

• • • • Adélie penguins: One of the truly Antarctic-endemic species, alongside the emperor penguin. They have black backs, white undersides, white eye rings, and black bills.

• • • • Chinstrap penguins: Identified by a black band running beneath the chin, red-orange eyes, and a black-and-white body.

Heidi then walked us through the life cycle of brush-tailed penguins. Breeding begins in October, when penguins return from the sea well-fed and ready to pair up, bringing colonies back to life in what she described as a wonderfully chaotic and deafening affair. While some species form long-term pair bonds, others are serially monogamous, reuniting with previous partners when possible but moving on quickly if not.

Courtship involves displays, tail-showing, and the gifting of pebbles, which are placed into nests built on bare ground. After copulation, the female lays one or two eggs and heads back to sea to replenish her energy reserves, while the male remains behind to incubate the eggs using his brood pouch. After 30 to 40 days, depending on the species, the chicks hatch. They are initially helpless and fed regurgitated krill by their parents.

As chicks grow, they form crèches for protection while adults forage at sea. Each chick has a unique call, allowing parents to locate them within the chaos of the colony. Once the chicks moult their down and develop waterproof feathers, they are chased into the sea by adults in what is effectively a baptism by cold water. After fledging, adults no longer associate with their offspring, heading back to sea to gorge on krill and prepare for their catastrophic moult, during which they replace all their feathers at once and remain land-bound for around two weeks. This energy-intensive cycle is repeated up to 15 times over a penguin’s lifetime, often at the same breeding site.

To finish her lecture, Heidi reminded us that despite their cuteness, penguins do have predators. Southern giant petrels may prey on adults, brown skuas work cooperatively to steal eggs and chicks, and snowy sheathbills scavenge carcasses and leftovers. She added, with a mix of horror and fascination, that sheathbills have even evolved to harass penguins during feeding, forcing them to regurgitate partially digested krill. Apart from birds, leopard seals are also formidable predators, particularly during fledgling season.

In this lecture, John started out by explaining the term pinnipeds, which refers to marine mammals with front and rear flippers that they use both to move on land and to swim in water. This clade consists of three major families:

• • Phocidae: Known as true seals or earless seals, as they have ear openings but no external ear flaps. These animals tend to crawl or flop on land, a movement known as galumphing. While they may look like oversized slugs on shore, their real prowess is seen underwater, where they use their rear flippers to propel themselves forward with remarkable efficiency. Most species are confined to temperate, polar, and subpolar regions.

• • Otariidae: Commonly referred to as sea lions, fur seals, or eared seals due to the presence of external ear flaps. They have a modified pelvic girdle that allows them to rotate their hind flippers forward, enabling them to walk upright or move on all fours on land. In the water, they rely primarily on their powerful front flippers for propulsion. These seals are mostly found in temperate, equatorial, and subpolar waters.

• • Odobenidae: This family contains only one extant species, the walrus, an unmistakable animal known for its enormous tusks and sensitive whiskers. Walruses are found in the Arctic regions of the Atlantic and Pacific Oceans and are not native to Antarctica. As usual, we focused only on the species we were likely to encounter during our expeditions.

• • • • Antarctic fur seal: An otariid found mainly around subantarctic islands. They have longer necks and more pointed muzzles than many other seals in the family, with males being larger, darker, and furrier, while females have a sleeker, velvety appearance.

Males, which have visible external genitalia unlike true seals, typically come ashore around November to establish territories. When females arrive, males aggressively defend their harems, often fighting rival males and occasionally attempting to prevent females from escaping. After mating, females undergo a gestation period of around seven to eight months and usually give birth to a single pup. During the perinatal period, the lanugo-covered pups grow rapidly and become increasingly mobile and inquisitive, before being weaned after roughly two to three months. After this, the adults return to sea to feed, beginning the cycle anew.

Antarctic fur seals were hunted to near extinction by the 1840s and survived only in small populations, particularly around South Georgia. Their numbers have since rebounded dramatically, now exceeding pre-sealing levels. This recovery is thought to be linked not only to legal protection but also to the decline of commercial whaling, which allowed krill populations to increase and better support seal populations. These animals were primarily hunted for their fur, with the dense underfur layer being considered “soft gold”, containing up to 250,000 hairs per square inch.

• • • • Southern elephant seal: Named for both their enormous size and the inflatable proboscis of adult males, southern elephant seals are the largest of all pinnipeds and phocids, and the largest marine mammals outside of cetaceans. Southern elephant seals are significantly larger than their northern counterparts. Sexual dimorphism in this species is extreme, with males weighing up to four times more than females and sporting a pendulous, trunk-like nose that develops around three years of age. This proboscis acts as a resonating chamber, amplifying their vocalisations during dominance displays.

Elephant seals are among the most accomplished divers on the planet. They typically spend only a few minutes at the surface before diving for an average of twenty minutes to depths of 400 to 1,000 metres, with recorded dives exceeding 2,400 metres. At these depths, they hunt squid and fish. Their diving ability is supported by remarkable physiological adaptations, including increased oxygen storage in blood and muscle, reduced oxygen consumption, the ability to collapse their lungs safely, and highly sensitive vibrissae that detect movement in near-total darkness. While less graceful on land, they are capable of surprising bursts of speed, using their powerful hind flippers to propel themselves forward.

Their breeding strategy is similar to that of fur seals. Males haul out between November and December and engage in intense competition for territory before females arrive, initiating the breeding season. After a relatively short lactation period, pups are weaned within around three weeks. Following breeding, adults undergo catastrophic moulting, shedding both skin and fur over a two-to-three-week period. During this time, they remain ashore, often lying in wallows made up of mud, faeces, sloughed skin, and the occasional rotting carcass. To make matters worse, after surfacing from deep dives, they are notoriously flatulent. As John put it, these are perhaps the only animals that smell better dead than alive, leaving him nostalgic for the comparatively fresh and invigorating scent of penguin colonies.

Southern elephant seals were hunted extensively for their blubber, which can be ten to twelve centimetres thick. Their habit of breeding on accessible beaches made them easy targets, and they were driven close to extinction before the decline of commercial sealing and the rise of whaling shifted exploitation elsewhere.

• • • • Leopard seals: An endemic Antarctic phocid and one of the continent’s apex predators, alongside orcas. They are named for the dark spots on their bellies, which can be used to identify individuals. Often described as reptilian in appearance, leopard seals are all muscle and engine, with streamlined bodies, large heads, and long pectoral flippers that grant them extraordinary agility underwater. They have thick, reinforced skulls that allow them to break through sea ice and powerful jaws armed with lobed teeth that function like sieves when feeding on krill.

Juveniles feed primarily on krill before expanding their diet to include fish, penguins, and occasionally other seals and small cetaceans. Leopard seals are solitary animals, spending most of their lives either in the water or hauled out on ice floes. Unlike many other pinnipeds, they exhibit minimal sexual dimorphism, aside from females being slightly larger and possessing mammary openings.

Breeding typically occurs in summer on pack ice. After a gestation period of roughly eight to nine months, females give birth to a single pup. Mothers nurse their pups for several weeks, during which they also appear to teach them basic hunting skills before abandoning them to fend for themselves. Due to their remote habitat and elusive behaviour, much about leopard seal life history remains poorly understood, making them one of Antarctica’s most enigmatic predators.

This lecture covered the different species of whales and dolphins found in the Antarctic, along with some of the more salient aspects of their individual behaviours, much of which is inferred from circumstantial evidence given that most of their lives are spent underwater. John likened our observations of them to starting a movie halfway through.

He began by explaining that the infraorder Cetacea consists of fully aquatic mammals such as dolphins, porpoises, and whales. These animals propel themselves using powerful tail flukes and manoeuvre with flipper-shaped forelimbs, and are renowned for their high intelligence and complex social behaviour. To this day, we still don’t know exactly why whales breach, one of their most spectacular behaviours. Some theories suggest it may be for play, exercise, parasite removal, or long-distance low-frequency communication.

Cetaceans are divided into two major groups: baleen whales, which filter-feed, and toothed whales, which actively hunt prey using teeth and echolocation. In the Antarctic, the most commonly encountered whales are humpback whales and orcas, with minke whales being a close third. John then went on to describe the cetaceans we were most likely to encounter:

• • Toothed whales: These make up roughly 90% of all cetacean species. They possess teeth adapted to capturing prey, with shape and number varying by family and genus. Toothed whales have highly developed sensory systems and rely heavily on echolocation for hunting and navigation. Most are social animals, living in groups known as pods.

• • • • Dolphins: Fast, agile predators that feed on fish and marine invertebrates. Their streamlined bodies, blubber layer, single blowhole, dorsal fin, and countershading make them exceptionally well adapted to life in the water. All dolphin species found in Antarctic waters have stable or thriving populations.

• • • • • • Hourglass dolphin: Often confused with orcas due to their striking countershading. These medium-sized, pelagic dolphins are usually seen offshore and frequently bow-ride ships, though they often disappear as quickly as they appear.

• • • • • • Commerson’s dolphin: Small and stocky, found in relatively large groups. Their distribution is limited to the southern tip of South America and the Kerguelen Islands. They have tiny fins, strong countershading, and are extremely playful, often drawn to engine noise and pressure waves. Known to travel long distances.

• • • • • • Dusky dolphin: Medium-sized with a dark grey body and a grey-and-white face. Highly acrobatic and playful, and closely related to southern right whale dolphins and common dolphins.

• • • • • • Peale’s dolphin: Small and similar to dusky dolphins but with a darker face. They possess one of the most highly folded cerebral cortices of any animal and are famously playful. According to John, they’re also very likely to show off by flipping in front of anyone holding a camera.

• • • • Orca: The largest member of the dolphin family, reaching lengths of up to nine or ten metres. Easily identified by their black-and-white countershading, white eye patch, small blow, and tall dorsal fin, which can reach up to two metres in adult males. Orcas are found worldwide but are usually coastal rather than pelagic, undertaking relatively short migrations between feeding grounds. They are capable of diving beneath thick sea ice with ease. In Antarctica, orcas are commonly classified into four types:

• • • • • • Type A: Large and primarily feed on minke whales.

• • • • • • Type B: Smaller, often yellowish due to diatom growth, and the most common type in southern oceans.

• • • • • • Type C: Even smaller, frequently spy-hop, found mainly in the Ross Sea, and feed mostly on fish.

• • • • • • Type D: The smallest and rarest type in Antarctic waters.

• • • • Porpoises: Similar to dolphins but with different skull morphology, stubbier beaks, and spade-shaped teeth. Dall’s porpoises are the largest porpoise species, with a stocky, countershaded body and occasional albino or melanistic individuals.

• • • • Beaked whales: Among the least understood cetaceans due to their deep-diving lifestyle and brief surface intervals. Cuvier’s beaked whale holds the record for the deepest and longest dives of any whale, reaching depths of nearly 3,000 metres. John mentioned that he had seen only two in his entire career, both in the Drake Passage. The extensive scarring seen on their bodies is thought to result from intraspecific combat or interactions with prey

• • • • Sperm whales: Long-lived animals, often reaching 70 years of age, and growing up to 15 to 19 metres in length. Their massive heads, which account for roughly a third of their body length, house the largest brain known to have existed on Earth. They are identifiable by their wrinkled grey skin, low dorsal hump, and a single blowhole positioned forward and to the left. The spermaceti organ within their head plays a role in buoyancy regulation, echolocation, and possibly acoustic focusing, and was historically exploited for oil, candles, and cosmetics.

These whales are pelagic and frequently dive to extreme depths in areas of nutrient-rich upwellings, feeding primarily on giant and colossal squid. When threatened, pods may form a defensive rosette or “marguerite” formation to protect vulnerable members from predators such as orcas. Their social structure is matriarchal, with females and young living together and adult males typically leading more solitary lives. Communication occurs through complex clicking patterns that resemble Morse code. Females have a gestation period of around 15 months, giving birth to a single calf every four to twenty years, with weaning lasting three to five years.

• • • • Baleen whales: Despite their enormous size, these whales feed on some of the smallest organisms in the ocean, mainly zooplankton and krill. Baleen plates, made of keratin, act as flexible filters. Water is taken into the mouth, and the tongue pushes it back out through the baleen, trapping food. Baleen whales have two blowholes and cannot echolocate, though they communicate using low-frequency sounds. Most follow predictable migratory routes, feeding in cold polar waters during summer and migrating to warmer, equatorial waters in winter to breed and nurse calves.

• • • • • • Humpback whale: Scientifically known as Megaptera novaeangliae, meaning “big-winged New Englander”, though they are found worldwide. Their name comes from the arching of their backs before diving. They can reach lengths of up to 17 metres and weigh around 36,000 kilograms. Their enormous pectoral fins can be up to a third of their body length. Humpbacks are easily identified by the shape of their blow, small dorsal fin, and the unique patterns on their flukes.

In the Southern Ocean, humpbacks primarily feed on krill using lunge feeding rather than the bubble-net techniques more common in the Northern Hemisphere. During a lunge, the whale accelerates rapidly, engulfing massive volumes of water and prey as its pleated throat expands. The water is then expelled through the baleen, leaving the krill behind. This feeding activity often attracts seabirds that take advantage of leftovers at the surface.

Although northern and southern humpback populations are genetically similar, they almost never mix. Both migrate toward the equator during winter to breed and calve, and toward the poles during summer to feed, without crossing hemispheres. These migrations also fertilise the oceans, as nutrients released from whale waste and sloughed barnacles enrich surface waters. Tracking data shows that humpback populations have rebounded significantly and are now approaching historical levels.

Humpbacks are also famous for their long, complex songs, produced mainly by males. These songs can last for hours and are thought to play roles in mating, navigation, and social communication.

• • • • • • Sei whale: The third-largest whale species, cosmopolitan in distribution. They can be distinguished from fin whales by their larger dorsal fin, asymmetric baleen colouring, and characteristic pockmarks on their skin. Sei whales are typically seen in small groups of two or three and were heavily hunted in the past, nearly to extinction, but are now slowly recovering.

• • • • • • Blue whale: The largest, loudest, longest, and heaviest animal to have ever lived. Blue whales can reach lengths of up to 30 to 35 metres and are blue-grey with a mottled pattern. Their blow can reach heights comparable to Old Faithful. Everything about them is massive, from their tongue, which can weigh as much as an elephant, to their heart, roughly the size of a small car. They can live up to 90 years, give birth every two to three years, and calves consume up to 250 litres of milk per day. An adult blue whale can eat up to 40 million krill daily.

• • • • • • Southern minke whale: The smallest of the baleen whales, reaching up to nine metres in length. Fast, curious, and dolphin-like in appearance, they are known to spy-hop, breach, and occasionally break through sea ice.

• • • • • • Southern right whale: A rotund, stocky whale with no dorsal fin. Historically known as the “right” whale to hunt due to their slow swimming, skim-feeding behaviour, and tendency to float when dead. They have V-shaped blows, black bodies with white callosities, and massive baleen plates. Though whaling brought them close to extinction, southern populations have fared better than their northern counterparts and are slowly recovering.

After this information overload spread across two lectures, we were encouraged to upload any decent photos we had taken to citizen science platforms such as Happywhale. These projects allow researchers to identify individuals and track migrations, social structures, and long-term population trends, highlighting just how valuable even casual observations can be.