Danger Rating

Extreme

Animals that cause serious harm without necessarily being lethal. Broken bones, deep wounds, and venom that ruins a week.

9 creatures

The 200-pound riverbed dinosaur with a spiked shell, a 1,000-pound jaw trap, and a pink worm wriggling on its tongue.

Air-bubble buoyancy, blue-and-silver countershading, and a sting borrowed from the Portuguese man o' war.

Giant round eyes, a 180-degree gape, and venom that turns the blood against itself.

A six-eyed night hunter with a violin marking and venom that can kill the tissue around a bite.

A sting rated level four, the top of Schmidt's pain scale, from one of the giant ants known in Brazil as the twenty-four-hour ants.

The solitary ghost cat of the Americas that can leap 40 feet in a single bound and purrs like a smaller cat.

Bead-armored venomous lizard, grooved chewing teeth, and Sonoran Desert survivor.

Up to 23-foot apex archosaur, and the species behind the highest bite force measured in any animal: 3,689 pounds.

The deceptively cute nocturnal primate whose elbow-gland secretion carries a protein closely resembling a cat allergen.