"Head of a Bear," drawn by Leonardo da Vinci, went on display at Christie's in New York on May 15. /CFP

The square drawing, measuring seven centimetres on each side, is a silverpoint drawing on a pink-beige paper. /CFP

It is "one of less than eight surviving drawings by Leonardo still in private hands outside of the British Royal Collection and the Devonshire Collections at Chatsworth," said the auction house. /CFP

The drawing will head to auction in July and is expected to fetch up to $16.7 million, according to Reuters. /CFP