Creatures known as “living fossils” have lasted for millions of years with barely a change. Many are now threatened or endangered. But with some luck and a little help, they may be able to survive the age of humans, too.
 
The Ant from Mars

Martialis heureka, better known as the "Ant from Mars," is a direct-line descendant of the last common ancestor of all ants -- a subterranean forager who wouldn't go above-ground until flowering plants evolved 120 million years ago.

Purple Frog

The Purple frog, discovered just five years ago in western India, lives underground. It emerges for just two weeks during the monsoon season. It's related to a family of frogs now found only on the Seychelles islands, which split from India 100 million years ago.

Frilled Shark

Scientists disagree over whether the frilled shark has survived for 380 million years or a mere 95 million years. Only two living specimens have been found, both off the coast of Japan. However, they are sometimes caught accidentally by deep-sea fishing nets.

Jurassic Shrimp

Until a preserved specimen was found in the Smithsonian in 1975, the 10-footed, lobster-like Jurassic shrimp was thought to have gone extinct 50 million years ago. Living Jurassic shrimp have since been found.

Three-Eyed Beetle

The Siberian Sikhotealinia zhiltzovae is the only three-eyed beetle. Some scientists consider it a forerunner of nearly all winged insects.

Velvet Worms

Found mostly in Southern Hemisphere rain forests, velvet worms have legs and bear live young, unlike other worms. Their legs are hollow and supported by fluid pressure. After a few early adaptations for land, they've hardly changed in 360 million years.

Crocodiles

The most widespread of all living fossils, crocodiles have barely changed in the 230 million years since dinosaurs roamed the Earth.

Duck-Billed Platypuses

One of the relatively few mammalian living fossils, duck-billed platypuses have been weird for 110 million years: in addition to their bills, they lay eggs and have venom-filled leg spurs. They are so strange that they were considered a hoax by early naturalists.

Nautiluses

Its spiraling chambered shell was a symbol of perfection in ancient Greece. The nautilus has changed little in 500 million years.

Horseshoe Crabs

Horseshoe crabs, found commonly on Atlantic beaches, are more closely related to spiders, ticks and scorpions than crabs. Their ancestors evolved in the Paleozoic's shallow seas, and they've evolved only slightly in the last 445 million years. They can regrow lost limbs, but can't right themselves when they’re upside down.

Coelacanths

Coelacanth vanished from the fossil record 410 million years ago, but then one was caught in 1938 off the coast of South Africa. A second species was discovered in Indonesian waters in 1999.

Mantis Shrimp

The mantis shrimp is neither a mantis nor a shrimp, and they have changed little in 400 million years. It has the world's most complex eyes, and its prey-killing claw motion is the second-fastest animal motion.