With spring break being observed in some parts of the country after Easter (instead of before), Dreamworks Animation/Fox's The Croods returned to No. 1 at the box office on Monday with $5 million in ticket sales, dropping just 20 percent from Sunday, according to Box Office Mojo. By contrast, Paramount's G.I. Joe Retaliation, which had held the top spot between last Thursday and Sunday, dropped 53 percent from Sunday, with $4.5 million in sales. Meanwhile, the BBC reported today that The Croods beat back G.I. Joe's assault on the box office in the U.K. The animated feature, it said, earned $5 million over the weekend versus $4.2 million for G.I. Joe. (The film had originally started out as a co-production between DWA and Britain's Aardman, with a script by John Cleese, before the partnership between the two studios was dissolved after two Aardman flops.) In third place was director Danny Boyle's thriller, Trance, with $2.5 million. The film is scheduled to open in the U.S. on Friday.