According to the San Francisco Chronicle, police found a shoe and blood in an area between the gate and the edge of the animal’s 25- to 30-foot-wide moat, raising the possibility that one of the victims dangled a leg or other body part over the edge of the moat…
One zoo official insisted the tiger did not get out through an open door and must have climbed or leaped out. But Jack Hanna, former director of the Columbus Zoo, said such a leap would be an unbelievable feat and ”virtually impossible.”
Instead, he speculated that visitors could have been fooling around and might have taunted the animal and perhaps even helped it get out by, say, putting a board in the moat.
Ron Magill, a spokesman at the Miami Metro Zoo, said it was unlikely a zoo tiger could make such a leap, even with a running start.
The story is here. And I agree with what Robin Hanson is probably thinking: it was signaling behavior. Maybe from the tiger too.
Update: Here is one story, here is more, some of you rail in the comments but the initial interpretation is looking correct. Note also that the tiger, after killing the first boy, went 300 yards to track down the other two boys and not anyone else.