When a third survivalist crashes the challenge, tension and jealousy are just as threatening as the piranha and jaguars of the Ecuadorian rainforest. Claims that there's more going on than just survival puts everyone's challenge at risk.

Dropped onto a frozen Alaskan Glacier, All-Star survivalists Laura Zerra and Steven Hall scramble to stave off frostbite and hypothermia. And 7,000 miles south, two new survivalists take on a sun-scorched Brazil island, with anaconda and deadly stingray.

A survivor of rattlesnake, shark and bear attacks teams with Brooke, wife of "Naked and Afraid" veteran Matt Wright, in a vicious African feeding ground.

All-Star survivalists Jake Nodar and Melissa Miller take on the punishing Blackwater Swamp in Florida, which teems with poisonous snakes and aggressive alligators. When one of the survivalists becomes disorientated, local authorities are called in to conduct an all-out search.

A haunted Colombian rain forest punishes the survivalists with threats from deadly jaguars, 300 species of snakes and relentless biting insects. But their challenge is threatened when they don't heed the curse of the jungle.

Pinned down by Africa's most dangerous threats elephants, hippos and lions, survivalists "Mama Kel" and Eric work together to avoid becoming prey and endure relentless storms, but a debilitating injury puts them both at risk.

Avoiding the dangers of a rushing river, two survivalists brave a vast cave system in the Colombian rainforest; trying to survive 21 days, the jungle tests them with threats including venomous fer-de-lance snakes, piranhas and biting insects.

Two pairs of survivalists are surprised when they must take on the deadly jungles of Panama side-by-side. But before their 21-day challenge begins, they have to re-think their survival strategies along gender lines.

Two fan survivalists are dropped on a Mexican island filled with venomous coral snakes, territorial jaguars, blood-sucking chiquistas and a duck named Henry that they desperately want to eat for dinner.

Elite survivalists Matt Wright and Gary Golding are tested by deadly spitting cobras and territorial elephants in an African killing zone. But Matt and Gary aren't alone each must protect a novice survivalist from the threats surrounding them.

Survivalists expect to struggle against the natural threats for 21 days but when they also face supernatural phenomena – haunted locations, ancient curses and evil spirits – their resolve is tested both physically and mentally.

On a sun-scorched Brazilian island, aggressive anaconda and deadly stingray torment survivalists Whitney and Nathan, pushing both of them to their breaking point. Working together they use their hunting and fishing skills to try and make it 21 days.

A deadly spider bite puts Gwen, an Alaskan homesteader at risk of tapping but she works with her partner to get her revenge, in the 130-degree heat of the Mexican jungle.

The first couple to ever take on the 21-day challenge tests themselves and their relationship as they take on the Guyana jungle. They must work together to battle jaguars, anacondas, caiman, and more than two-million species of insects.

Dropped into a high-altitude jungle in Colombia, Tommy and Leah face territorial Pumas and venomous fer-de-lance snakes, but the biggest threat is the extreme temperature changes, where highs hit nearly 100 degrees and lows plummet into the 40s.

Being naked in the jungle with a complete stranger can lead to funny moments, and laughter can be a critical skill when trying to survive through blood, sweat, tears, snake bites, burns, and rashes in hard to reach places.

In the mountainous rainforest of Honduras, a survivalist with an unusual past is paired with a hard-headed police detective to try and survive 21 days, but predatory jaguars, swarms of fire ants and a debilitating injury threaten their challenge.

In sun-scorched Brazil, survivalists Wes and Jesse try to complete their 21-day challenge, but a jaguar crossing into their camp puts them on high alert. Starvation forces Jesse to attack a beehive in search of honey and the entire colony retaliates.

In sun-scorched Brazil, survivalists Wes and Jesse try to complete their 21-day challenge, but a jaguar crossing into their camp puts them on high alert. Starvation forces Jesse to attack a beehive in search of honey and the entire colony retaliates.

Dropped into Guyana's scorching savannah, two Naked and Afraid superfans fight the oppressive heat and constant insect attacks. Scorching temperatures lead to severe dehydration and force a desperate fan to risk illness by drinking unsanitary fluids.

Surviving 21 days Naked in the wilderness leads to weird and awkward moments. From bizarre pre-challenge prep and mortifying naked intros, to night-time cuddling gone wrong and learning wildlife bathroom routines the hard way, Naked and Afraid gets weird