Level 1 - Absolute Beginner
Scientists found a very old footprint in Antarctica. The footprint is 55 million years old. It is a print of a hand and a foot together. Scientists call it a fossil.
A fossil is something very old that turned into rock. This fossil was found on King George Island. The footprint was in old mud that came from a volcano. The mud turned hard like stone.
This is the first footprint from a mammal ever found in Antarctica. A mammal is an animal like a cat or a dog. The animal that made this footprint ate meat. It was small, about the size of a housecat.
Long ago, Antarctica was warm, not cold and icy like today. Land connected Antarctica to South America. Animals could walk between the two places. This footprint helps scientists learn about that time.
- footprint
- A mark left by a foot or hand on the ground.
- fossil
- Something very old, like a bone or footprint, that turned into rock.
- mammal
- An animal that has fur and feeds milk to its babies, like a cat or dog.
- Antarctica
- The very cold continent at the bottom of the world.
- volcano
- A mountain that can shoot out hot melted rock.
- meat-eating
- An animal that eats other animals for food.
- scientist
- A person who studies and learns about the world.
- million
- A very big number: 1,000,000.
Level 2 - Elementary
Scientists have discovered a fossil footprint on King George Island, near Antarctica. The footprint shows the shape of an animal's hand and foot. It is 55 million years old, from a time called the Eocene epoch.
The footprint was found in a layer of rock called the Fossil Hill Formation. Long ago, this rock was soft, wet mud from a volcano. The animal stepped in the mud, and over millions of years, the mud turned into hard rock, keeping the footprint safe inside.
This footprint is special because it is the first trackway from a mammal ever found in Antarctica. A trackway is a set of footprints left by a walking animal. It is also the earliest sign of a meat-eating mammal on the continent.
By studying the size and shape of the footprint, scientists think the animal weighed about 1.3 kilograms, similar to a small housecat. It probably looked like an extinct group of animals from South America called sparassodonts. These were carnivorous mammals that carried their babies in pouches, like modern kangaroos.
- fossil footprint
- A footprint that has turned into hard rock over a very long time.
- epoch
- A long period of time in Earth's history.
- rock layer
- A flat section of rock that formed at a certain time in the past.
- trackway
- A line of footprints made by an animal as it walked.
- carnivorous
- Describing an animal that eats meat.
- extinct
- No longer living anywhere on Earth.
- pouch
- A pocket of skin some animals use to carry their babies.
- continent
- One of the seven very large areas of land on Earth, such as Antarctica.
Level 3 - Intermediate
Researchers examining rock formations on the Fildes Peninsula of King George Island, part of the South Shetland Islands off the Antarctic Peninsula, have identified a fossilized footprint unlike anything previously documented on the continent. Catalogued as specimen T-373, the partial manus-pes print, meaning a combined hand and foot impression, was preserved in ancient volcanic mud that hardened into rock over 55 million years.
The find, published in the journal Polar Biology in 2026, dates to the Eocene epoch and was recovered from a layer of rock known as the Fossil Hill Formation. What makes it remarkable is not its size but its significance: it is the first known trackway left by a mammal ever discovered in Antarctica, and it represents the earliest evidence of a carnivorous mammal anywhere on the continent.
Analysis of the footprint's dimensions and shape allowed researchers to estimate the animal's weight at roughly 1.3 kilograms, comparable to a small housecat. Its features suggest a resemblance to sparassodonts, an extinct lineage of South American predators. Sparassodonts were carnivorous marsupials, meaning they were pouched mammals related to today's opossums and kangaroos, rather than to placental predators like dogs or cats.
The discovery reshapes assumptions about Eocene Antarctica's ecosystem. Rather than a simple environment, the fossil record now points to a more diverse community of carnivorous mammals and a more complex food chain than researchers had previously documented. This fits a broader picture of the era: 55 million years ago, Antarctica had a far warmer climate and remained connected to South America and Australia by land bridges, allowing animals to migrate between continents before Antarctica later became isolated and ice-covered.
- specimen
- A single example of something collected for scientific study.
- manus-pes print
- A fossil impression that shows both a hand (manus) and a foot (pes) together.
- peninsula
- A piece of land that sticks out into the sea, connected to the mainland.
- sparassodont
- A member of an extinct group of carnivorous, pouched mammals from South America.
- marsupial
- A mammal that carries and nurses its underdeveloped young in a pouch.
- placental
- Describing mammals whose young develop fully inside the mother before birth, unlike marsupials.
- land bridge
- A strip of land connecting two landmasses, allowing animals to cross between them.
- ecosystem
- A community of living things interacting with their environment.
Level 4 - Advanced
A single fossilized track, catalogued as specimen T-373, has upended assumptions about the mammalian history of Antarctica. Discovered on the Fildes Peninsula of King George Island in the South Shetland archipelago, the partial manus-pes impression, preserving both hand and foot, was cast in volcanic mud roughly 55 million years ago, during the Eocene epoch, and subsequently lithified within the stratum now known as the Fossil Hill Formation.
Published in Polar Biology in 2026, the find constitutes the first documented mammalian trackway from the Antarctic continent and, notably, the earliest evidence anywhere in Antarctica of a carnivorous mammal. Prior evidence of Eocene Antarctic mammals has come almost entirely from skeletal fragments and teeth; a trackway offers a different, behavioral line of evidence, capturing an animal's locomotion rather than merely its anatomy.
Morphometric analysis of the print's dimensions places the trackmaker at approximately 1.3 kilograms, roughly the mass of a small housecat, with features consistent with the sparassodonts, an extinct radiation of South American carnivorous marsupials. That the closest analogue is a marsupial lineage, rather than a placental one, is itself consequential: it situates the trackmaker within the broader Gondwanan marsupial fauna that once ranged across the interconnected landmasses of the Southern Hemisphere.
The implications extend beyond a single footprint. Researchers argue the find is evidence of a more taxonomically diverse assemblage of carnivorous mammals, and by extension a more intricate trophic structure, than the sparse Eocene Antarctic fossil record had previously indicated. The context is climatic as much as biological: 55 million years ago, Antarctica retained a temperate climate and stood connected to South America and Australia via land bridges, corridors that permitted faunal exchange across the ancient supercontinent of Gondwana before tectonic separation and subsequent glaciation isolated the continent under its present ice sheet.
- lithify
- To turn into solid rock through natural geological processes.
- stratum
- A distinct layer of rock, typically one of several layers formed over time.
- morphometric
- Relating to the measurement and analysis of the shape and size of an organism or fossil.
- trackmaker
- The animal that produced a given set of fossil footprints.
- Gondwanan
- Relating to Gondwana, the ancient southern supercontinent that included Antarctica, South America, Africa, and Australia.
- trophic structure
- The layered feeding relationships within an ecosystem, from prey to predator.
- faunal exchange
- The movement of animal species between regions, often across land connections.
- radiation (evolutionary)
- The rapid diversification of a group of related species from a common ancestor.
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