Two fisherman play tug-of-war with a massive croc. A father and son get caught in a wildfire. And a bow hunter gets a bear hug.

Hunters get a visit from a tree-climbing bear. A man drives head-on into a tornado. And a belligerent bull moose stops a couple of snowmobilers in their tracks.

A forest comes toppling down onto terrified motorists. An acrobatic bear shows off his high wire act. And porta pottys take flight.

A buck crashes the party at a beauty salon. A cobra hitches a ride. And a Bayou swamp goes down the drain.

A paraglider is swept up by a freak wind storm. An avalanche buries hikers in the Himalayas. And an emu falls in love.

A jogger has a terrifying run-in with a cougar. An elephant commits highway robbery. And an octopus does a disappearing act.

A man finds his inner beast to scare a bear away. Boaters run for their lives from an erupting volcano. And a freak dust storm steals second base.

A seal finds an eight-legged weapon. A dog rescues a drowning deer. And a town crumbles into the sea.

High above the Himalayas, a paraglider becomes entangled with a vulture, bringing both down to earth. Kayakers are almost swallowed by a whale. And a tidal bore washes motorists off the road.

Campers experience the raw power of a lightning strike. A massive boulder demolishes a car. And a gorilla has his way with a tourist.

An Impala finds an unlikely escape from a cheetah. A skier is buried alive. And a paraglider dukes it out with a kangaroo.

The worst avalanche in recorded history wreaks havoc on the Everest basecamp. A fisherman dives into the deep sea to save a whale. And an orangutan finds a friend and won't let go.

How has our ability to communicate defined us as a species? Sharing information with each other has allowed humans to rise to the top of the food chain and dominate our environments. But humans aren't the only species that can communicate. Organisms as simple as bacteria can communicate, a strategy that lets them cooperate to take down creatures millions of times their own size. Fish use pheromones to warn each other about predators and find mates. Chemicals are also an effective means of communicating on land, and they've allowed insects--some of nature's smallest and most unassuming animals--to become the most populous and prolific on earth. The ability to interact stretches back billions of years and has often been one of the primary factors in a species' ability to evolve and survive.

They are one of evolution's most useful and prevalent inventions. Ninety-five percent of living species are equipped with eyes, and they exist in many different forms. Learn how the ancestors of jellyfish may have been the first to evolve light-sensitive cells. Discover how dinosaurs evolved eyes that helped them become successful hunters. Finally, learn how primates evolved unique adaptations to their eyes that allowed them to better exploit their new habitat and how the ability to see colors helped them find food.