Fossilised remains of a giant bird up to three times bigger than an ostrich, which scientists believe once roamed Europe, have been discovered in Crimea.
Based on a fossilised thigh bone uncovered in the Taurida Cave on the northern coast of the Black Sea, researchers estimate that the flightless creature weighed around 450kg and stood nearly 4.5 metres tall, towering over early humans between 1.5 and two million years ago.
It is said to be the first time a bird so large has been reported from anywhere in the northern hemisphere.
"When I first felt the weight of the bird whose thigh bone I was holding in my hand, I thought it must be a Malagasy elephant bird fossil because no birds of this size have ever been reported from Europe," said Dr Nikita Zelenkov, from the Russian Academy of Science, lead author of the findings.
"However, the structure of the bone unexpectedly told a different story."
Although the bird was flightless, scientists believe it was fast because of its long, slim thigh bones, which may have been an essential part of its survival.
It is thought to have belonged to a species known as Pachystruthio dmanisensis, and could have been a source of meat, bones, feathers and eggshell for the first humans to settle in Europe from Africa.
Writing in the Journal of Vertebrate Paleontology, scientists said that, while the species was previously known, it is the first time anyone has attempted to calculate the size of it, using measurements of the femur bone to calculate its weight.
This would make it nearly double the largest moa, three times as big as the common ostrich, and nearly as heavy as an adult polar bear.
The discovery was made by chance last summer during the construction of a new motorway, alongside other specimens including a bison.
