A little penguin standing on the St Kilda breakwater at dusk weighs about a kilogram and stands roughly 30 centimetres tall. An emperor penguin standing on Antarctic sea ice weighs up to 40 kilograms and stands well over a metre. Both are penguins. That gap alone tells you most of what you need to know about why lumping “penguins” into one mental picture of snow and ice gets the story wrong.
We get asked some version of this a lot on the breakwater: “but don’t penguins live in the snow?” Fair question, and an honest one. It’s just not true for the birds waddling past your feet at St Kilda, and it’s not true for most of the world’s penguin species either. Only two of them, the emperor and the Adélie, spend their lives on actual Antarctic ice. The rest are spread across a surprising stretch of the Southern Hemisphere, from the equator to the sub-Antarctic islands, and quite a few of them live somewhere closer to beach weather than blizzard weather.
Seventeen or eighteen species, depending who you ask
Taxonomists don’t fully agree on the number, which is itself a useful thing to know if you want to sound informed rather than parrot a factoid. Most authorities count 17 or 18 living species of penguin, split across six genera. The disagreement usually comes down to whether certain rockhopper or crested penguin populations are separate species or subspecies, an argument that has run for decades and shows no sign of resolving soon. BirdLife Australia’s species accounts and the IUCN’s assessments are the two references we’d point you to if you want the current state of play rather than a number that was accurate in 1995 and has been repeated uncritically ever since.
What matters more than the exact count is the spread. Penguins occur from the Galápagos Islands, essentially on the equator, down to the frozen continent itself. That’s a range of something like 9,000 kilometres of latitude, across desert coastlines, temperate southern Australia, sub-Antarctic tussock islands and genuine polar ice. No other group of flightless seabirds comes close to that spread. It’s also why “penguin” as a shorthand for “cold climate bird” falls apart the moment you actually look at a distribution map.
The little penguin sits at one end of a size scale, not in a category of its own
Eudyptula minor, the species that breeds at St Kilda, is the smallest penguin alive. At around 1 kilogram and 30 centimetres it’s dwarfed by nearly everything else in the family. King penguins run to 15 kilograms. Emperor penguins, the largest living species, reach 35 to 40 kilograms and stand over a metre tall, built for a climate where losing body heat is the actual threat, not overheating.
Little penguins evolved the opposite problem. Their range covers the temperate coastlines of southern Australia and New Zealand, where the challenge in summer is more likely to be heat stress than hypothermia, which is part of why colony management on the breakwater includes checking for signs of heat distress during hot spells, not just cold ones. Smaller body size sheds heat faster relative to body mass, which suits a bird that forages in relatively mild coastal water year-round rather than needing the insulating bulk to survive months of polar winter. If you want the detail on how that plays out season to season at this specific colony, our penguin calendar and seasonal life cycle page runs through the breeding and moult timing month by month.
I’ll admit this is the fact I most enjoy correcting on a guided night, because the assumption runs so deep. People arrive expecting something built for cold. What they get is a bird built for a mild harbour, and once you say it out loud the confusion usually clears in about ten seconds.
Climate zones penguins actually occupy
Break the group down by climate rather than by taxonomy and the picture gets clearer fast.
Two species, the emperor and Adélie, are true Antarctic specialists, breeding on or very near pack ice and enduring conditions no other penguin experiences. A handful of species, including chinstrap, gentoo and macaroni penguins, occupy the Antarctic Peninsula and sub-Antarctic islands such as South Georgia, where conditions are harsh but not the full continental extreme. Further north again, king penguins breed on sub-Antarctic islands with a milder maritime climate. Then there’s a large group, including rockhopper, Fiordland, Snares and erect-crested penguins, that live on cool temperate islands around New Zealand and the southern oceans, none of them anywhere near ice for most of the year.
At the warm end, African penguins breed on the coast of South Africa in a climate most Melburnians would call pleasant, Humboldt and Magellanic penguins occupy the temperate to subtropical coasts of Chile and Peru, and Galápagos penguins live right on the equator, cooled only by the Humboldt Current rather than by any proximity to ice. Little penguins, our little penguins, sit in that temperate coastal bracket alongside African and Magellanic species: mild winters, warm summers, ocean-driven rather than ice-driven.
The pattern that actually explains penguin distribution isn’t latitude, it’s cold ocean currents. Every warm-climate penguin population sits on a coastline fed by a cold current rich in the small fish, krill and squid they need. Cut the current, lose the penguins, no matter how far from Antarctica you already are. Port Phillip Bay’s own food supply for the St Kilda colony works on a smaller version of the same principle, which we cover in more depth in why Port Phillip Bay’s water quality decides what St Kilda penguins eat.
Why the misconception persists
Documentary footage does a lot of the damage here. Decades of nature programming built around emperor penguins marching across ice shelves have given the entire family a single, dramatic, extremely photogenic representative, and that image has stuck harder than any textbook caption correcting it. It’s not really anyone’s fault. Emperor penguins are a genuinely remarkable story, breeding through the Antarctic winter in temperatures that would kill most animals outright. But the coverage they get is wildly out of proportion to how representative they are of the species as a whole.
Museums Victoria’s general fact sheets on penguin biology and the CSIRO’s marine research on Southern Ocean ecosystems both make the same point from different angles: penguin adaptation is about cold ocean water, not cold air, and those two things overlap far less than people assume. A bird can live somewhere with a pleasant Mediterranean-style climate on land and still depend entirely on a cold nutrient-rich current a few kilometres offshore.
If you want the fuller myth-busting version specific to this colony, we’ve written it up directly at why St Kilda’s penguins have nothing to do with Antarctica. Worth the read if you’re bringing family who’ve only ever seen the emperor penguin documentaries and arrive expecting snow.
What this means for a colony seven kilometres from the CBD
St Kilda’s colony is unusual for reasons that have nothing to do with cold at all. It’s the only mainland breeding colony of little penguins in Victoria sitting inside a major city, formed inside the cavities of a rubble-stone breakwater built in 1955 as part of the pier upgrade, never planned or engineered for wildlife. The birds simply moved in and stayed. That’s a genuinely strange origin story by penguin standards worldwide; most colonies occupy natural burrows, vegetated dunes or ice, not a human-built rock wall metres from a working harbour.
Professor Mike Cullen of Monash University started the long-term study of this colony in 1986, prompted by a harbour redevelopment proposal, running fortnightly night trips with the help of Neil Blake from St Kilda Council. That monitoring tradition, now carried on by trained volunteers, is one of the reasons this colony’s population and breeding data go back further than most urban wildlife records in Australia. It’s a proper long-term dataset, not a guess.
Comparing colonies is where the size and climate story gets genuinely interesting rather than just trivia. St Kilda is small and urban; Phillip Island runs a much larger colony with a different monitoring and viewing model entirely, and we’ve laid out exactly how those two compare in St Kilda vs Phillip Island: comparing colony size and monitoring and, on the visitor side, in St Kilda vs Phillip Island: why one colony is free and one isn’t.
Same behaviours, wildly different settings
What’s striking once you actually compare species side by side is how consistent the core penguin playbook stays across such different climates. Nearly every species is monogamous season to season, most reuse the same nest site year after year, all of them come ashore to breed and moult and all of them fast during the moult because they cannot swim and feed with damaged, non-waterproof feathers. Little penguins follow that pattern exactly: courtship from late July, eggs laid August through early November, chicks fed on whole small fish, then a roughly two-week moult each summer during which an adult burns stored fat and cannot go to sea at all.
An emperor penguin does something recognisably similar in temperatures 70 degrees colder. That consistency across such an extreme climate range is, to me, the actually remarkable part of penguin biology, more so than any one species’ size record. Evolution found one basic solution and then stretched it across almost every coastal and polar climate the Southern Hemisphere has to offer.
Next time you’re at the breakwater after dusk, waiting for the first arrivals to porpoise in through the swell, it’s worth remembering you’re watching one very successful variant of a much bigger story. Nothing about that bird needs ice. It needs a cold current, a safe cavity in the rocks, and a bit of dark to come home in.
