Antarctica's fauna is almost entirely marine—animals that breed on land/ice but feed in the Southern Ocean. No terrestrial mammals, no native humans. Here are the iconic species.
| Species | Population | Key Traits | Where |
|---|
| Weddell Seal | ~800k | Deepest diver (600m, 80 min), southernmost mammal, vocal | Fast ice, Weddell Sea, Ross Sea |
| Crabeater Seal | ~15-40M | Most abundant large mammal, specialized krill-filtering teeth | Circumpolar pack ice |
| Leopard Seal | ~35k | Apex predator (penguins, seals, krill), solitary, spotted coat | Pack ice, peninsula |
| Ross Seal | ~100k | Rare, large eyes, siren-like calls, Ross Sea specialist | Ross Sea, heavy pack ice |
| Southern Elephant Seal | ~750k | Largest seal (males 4t), extreme sexual dimorphism, trunk | Subantarctic islands, Antarctic coast |
| Antarctic Fur Seal | ~4-5M | Eared seal, dense fur, breeding harems, near-extinct 1900s | South Georgia, South Shetlands, Bouvet |
Penguins — 4 True Antarctic Breeders
| Species | Height | Population (Pairs) | Signature |
|---|
| Adélie | 70 cm | ~3.8M | White eye ring, "tuxedo," stone nests |
| Emperor | 115 cm | ~600k | Winter breeding, male incubation, deepest diver |
| Chinstrap | 70 cm | ~8M | Black chin line, steep colonies, noisy |
| Gentoo | 80 cm | ~300k | Orange bill, white bonnet, fastest swimmer (36 km/h) |
King, Macaroni, Rockhopper breed on subantarctic islands (South Georgia, Heard, Macquarie).
Birds (Beyond Penguins)
- Snow Petrel — pure white, breeds inland nunataks
- Antarctic Petrel — cliff colonies, krill feeders
- South Polar Skua — predator/scavenger, steals penguin eggs/chicks
- Wilson's Storm Petrel — "Jesus bird," patters on water, abundant
- Southern Giant Petrel — massive wingspan, carrion
Marine Giants (Cetaceans)
- Blue Whale (Antarctic subspecies) — largest animal ever, krill specialist
- Fin, Sei, Minke, Humpback, Southern Right — summer feeders
- Orca — ecotypes (Type A: minke hunters; B: seal specialists; C: fish; D: subantarctic)
- Hourglass Dolphin — only small cetacean regular in Antarctic waters
Invertebrates & Microfauna
Antarctic Krill (Euphausia superba): ~500 Mt biomass—largest single-species biomass. Keystone. Nematodes, tardigrades, rotifers, springtails, mites in soil/moss. Midge (Belgica antarctica) — only native insect, 2-6 mm, freeze-tolerant.
Protection
Antarctic Treaty System (1959), CCAMLR (1982), Madrid Protocol (1998). No hunting, mining, military. Science only. Climate change = existential threat (ice loss, krill decline, acidification).
Wanderlust World