Teach N Treat - Level 1

I broke out the Teach 'N Treat this weekend to see how well Pinniped and Bertie would do with it.  This puzzle is intended for guinea pigs, rabbits and other small animals.  It has eight depressions to put bits of food in, and three different levels of complexity to get to the prize.

I set it up for the easiest level.  The goal is to move a large disk away to expose the treats.  They managed to pull out the first two tomatoes within seconds.  I was shocked that Pinniped accomplished this so quickly (it took her several tries to work the egg-cersizer).  But it was obvious that neither pig had a clue how the tomatoes suddenly became available.  Bertie kept testing if she could bite through the plastic, and tried to pick up the disk.  At one point, she successfully shoved away the disk, but was so focused on it that she missed the fact she had uncovered two tomatoes.  Then Pinni attempted to steal what was left of Bertie's tomato, completely oblivious of the one in the hole she was standing over.  Silly pigs.

The Teach 'N Treat is large, but stationary, whereas the egg-cersizer will wander to wherever the pigs push it.  Both worked well on the kitchen floor when the girls were let loose.  The Teach 'N Treat doesn't work well in the cage, though:  it takes up too much floor space.  The egg-cersizer becomes more challenging in the limited space, since it tends to get jammed up in the corners and doesn't roll easily on shavings.

Bertie and Pinni had no problem understanding there were treats behind the plastic, and set to work on the Teach 'N Treat immediately.  But no one figured out how to get to the last tomato.  So I think I'll keep this on the easiest level a few more times, and see if they get the cause-and-effect of moving the disk.  Who do you think will master it first?