The curators are trying to get Marvin to eat the foods he needs to grow.  He tends to be a very fussy eater, and when he does eat, he is like a typical baby – very messy with his food!  Look what happened when they introduced full fat yogurt and he actually likes it. . .

Marvin picks grapes out of his bowl of yogurt.

He separated the grapes from the yogurt, saving them for later.

Marvin is not a neat eater!

Marvin gives paws up to yogurt, but paws down to formula.

After eating, he climbs in his pen.

The fact that he is climbing is a good thing – this shows the curators that he is not sick, but he surely is picky about his food!  He needs fat to put on weight.  The yogurt will help immeasurably, but they would like to see him eat the formula.  To make it more palatable for him, they are trying the formula-porridge mixture with additional ingredients like honey, applesauce, and vanilla flavoring.  So far he is resisting the formula, but they will keep trying!