My brother used to work at our local park board. They had a tame beaver that they used to take to grade schools as part of their wildlife presentations.

For their "demonstration" food, they used to cut off mulberry trees at ground level in the fall. In the spring, they would gather a few of the 6-8' tall new shoots. My brother would give the beaver the thicker end, and the beaver would then eat the entire shoot just as quickly as his little hands could shove it in his mouth.

My brother said the giggle rate for 2nd graders was 100% while watching the beaver eat!