And now, our toddler … Q: I want to hear what the loudest thing in the world is! — Kara Jo, age 5 No. No, you really don’t. See, there’s this thing about sound that even we grown-ups tend ...

World's loudest primate, the howler monkey, can emit a call or piercing scream that can reach up to 90 decibels and be heard up to 4.8 km away ...