A 6-year-old boy who was attacked by a tiger at a school assembly in Scotts Valley went home today after spending the night in a hospital to treat gashes on his head. The female tiger, called Sima, was being led on a leash out of an auditorium at Baymonte Christian School by her trainer yesterday afternoon when police say she lunged over a row of seats and grabbed the boy´s head in her jaws. The tiger´s owners, a nonprofit called Zoo to You Wildlife Education Incorporated, say the incident wasn´t an attack at all. They say Sima saw several children jump up and wanted to join in the fun and say the boy´s head was cut by silver medallions on the handler´s belt when she tried to separate them. David Jackson, director of Zoo to You Wildlife Education Incorporated, says he´s just glad the boy is O-K. A spokesman for Stanford Medical Center says doctors still aren´t sure what caused the 5-inch lacerations.