What do kangaroos eat?

• 7YO: "Dad, I have a really great question: What do kangaroos eat?"
• 10YO: "I think grass and weeds."
• DAD (Me): "Maybe zebras?"
• 4YO: "NNNOOOO! They eat grass and weeds because they can't defeat anybody. They're just kangaroos."
• (Obviously, it's time to relay some research to my 4YO about kangaroos boxing. Good teaching moment.)