Remarkable footage of elusive narwhal – creatures best known for their unicorn-like tusks – has been captured.
The BBC filmed the whales during their summer migration, as they navigated through cracks in the melting Arctic sea ice.
The team believes this aerial footage, which forms part of the BBC Natural History Unit’s new series Nature’s Great Events, is the first of its kind.
Also worth checking out: world’s largest snake found.
Titanoboa was 13m (42ft) long – about the length of a bus – and lived in the rainforest of north-east Colombia 58-60 million years ago.
The snake was so wide it would have reached up to a person’s hips, say researchers, who have estimated that it weighed more than a tonne.