World's Laziest: Why Do Koalas Have Chlamydia?

World's Best Builders: Can Beavers Fell Trees As Tall As A 10-Story Building?

World's Craziest Bugs: Our First Guest Episode

World's Spookiest: Is Bigfoot Real?

World's Silliest: Are Giant Pandas Really As Dumb As We Think?

World's Most Misunderstood: This Is Why We Need Mosquitoes

World's Most Unnoticed: Can Squirrels Be As Big As Humans?

World's Rudest: Swearing Parrot Gets Taken Off Display After Saying Something Really Bad

World’s Stickiest: How This Frog Turns Ants Into Armor

World's Crankiest: Do Lemmings Jump Off Cliffs?

World’s Yappiest: How Trees Talk To Each Other

World's Darkest: Can this shark live 500 years?

World's Most Disproportionate: Why Is This Monkey's Nose So Big?

World's Oldest: Was This Bird Bigger Than A Jet?

World's Hottest: Can This Worm Survive In Boiling Water?

World's Stealthiest: Can This Octopus Really Go Invisible?

World's Loudest: Can Sperm Whales Kill With Just Their Voice?

World’s Smelliest: This Bird Vomits as Self Defense

World's Roundest: Can Eating This Fish Kill You?

World's Rarest: Are Turtles Going Extinct?