Composite skeleton of a woolly rhinoceros, a companion of the woolly mammoth. This skeleton is assembled from more than 150 different skeletal parts of animals that were all approximately the same size and age. These bones were retrieved from the bottom of the North Sea and date back to a time when the North Sea between the British Isles and the Netherlands was dry land. It was part of the cold, dry, and nearly treeless grass steppe known as the mammoth steppe. This steppe stretched from the British Isles in the west across Europe and Asia to the New World in the east. The woolly rhinoceros was a common sight, especially in lowlands where sufficient food (grasses) was available. However, the woolly rhinoceros has never been found in North America. A large number of skeletal parts of these rhinoceroses have been found in the North Sea, but complete skeletons have never been recovered. The horns, both the nasal horn and the forehead horn, were made of keratin – essentially compacted hair – and have been recreated for this skeletal display.