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When the Arctic was a hot and tropical place, many large mammals roamed the land.  Although the Arctic was warmer in temperature than today, many mammals living north of the Arctic Circle experienced months of complete darkness and 24-hour summer days.

Image: A Coryphodon tooth.

3D View: Coryphodon
A reconstruction of Coryphodon in a forest.

Why this species is important

The Coryphodon (its scientific name) was a large mammal that roamed the Arctic from 51 to 59 million years ago, becoming one of the largest mammals to exist in the area since the extinction of the dinosaurs.  Living in warm swampy forests, this creature moved slowly and had very strong neck muscles, short tusks and short legs.

Scientists have excavated Coryphodon fossils on Ellesmere Island in the Canadian Arctic, including a Coryphodon tooth molar.   Through chemical studies of fossil bone, scientists have discovered that in the summer, Coryphodon ate flowers, leaves and swamp plants. In the winter dark, they munched on pine needles and fungi.


The Continental Drift

The Earth is constantly changing.  Over millions of years the planet’s continents have shifted and continue to do so today.  This geological phenomenon is known as the Continential Drift.

Associated with these drifts are specific geological time periods when air temperature and life on Earth was very different than present day.

This interactive image shows how the Earth’s continents have shifted over millions of years.  400 million years ago the Earth’s land masses were close to one another and near the equator.  Around every 100 million years there were major landmass shifts. By 10 million years ago, the Earth’s continents were located in their current positions.

A map of the world showing the continents shifting between 400 and 10 million years ago.
10 million years ago
400 million years ago

Brain to body ratio


Once the biggest mammal of its time, the Coryphodon was a large creature weighing about 500 kg, about the size of a modern-day hippopotamus.  Its brain size, however, only weighed around 90 grams, distinguishing it as having one of the smallest body-to-brain ratios of any mammal.


What is in a tooth?


Scientists have discovered a Coryphodon’s diet by studying its teeth.  This study not only reveals what the creature ate but also its behaviour.  Many animals migrate to warmer climates as the winter months approach.  The Coryphodon did not migrate and instead switched between two seasons and two types of food sources.


The last of its kind


All species on Earth evolve or become extinct.  Coryphodon is one mammal that became extinct and no other mammals are currently known to have evolved from it.