The odd item, which the movie star bought at auction for $276,000 (£172,500), is one of many collectors pieces up for sale or in foreclosure - made necessary by the fact Cage owes $6 million (£3.75 million) in back taxes.
Listing the movie star's collectables, New York magazine reveals the ancient skull wasn't the actor's only elaborate indulgence - he also owns a jet and two yachts, three castles, two islands in the Bahamas and "a dozen or so" mansions.
His 50 cars include a $495,000 (£309,375) Lamborghini once owned by the Shah of Iran.