Blue Sky Studios’ series of family-friendly cartoons about the adventures of three prehistoric chums – Manny the mammoth, Sid the sloth and Diego the sabre-tooth tiger – gears up for a fourth instalment. Its predecessor, Dawn of the Dinosaurs, is currently the fourth highest-grossing animated film of all time, making this follow-up wholly inevitable. This time, the movie is setting out to sea, as the continents begin to shift and our heroes are set adrift on a floating iceberg, where they encounter pirates, sea monsters and discover a new country.