The realm of cold is a harsh territory, but it is also full of opportunities; only the most resilient creatures manage to thrive in an environment where adaptation is the key to survival.

We delve into dense jungles where humidity dictates all aspects of life; creatures here not only contend with predators and the search for food, but also with diseases that thrive in high moisture.

In the most arid regions of the planet - where relentless heat dominates day and night - animals face one of nature's greatest challenges: survival in extreme temperatures.

Scientists are uncovering new truths about cats using tech like tracking collars; from cheetahs' agility to Iberian lynx recovery, groundbreaking research and conservation offer hope for wild cats.

Gary, Arlie and Jake search for a gator in an RV park, Shannon finds a timber rattlesnake at a local business, and the team trade gators with their sister park in South Padre Island, Texas.

In the dead of winter, Alaskans travel high, far and wide to obtain resources for survival. Glenn pursues caribou in the mountains of the Brooks Range.

Alaskans must trap and hunt for essential food and fur to survive dark winter. In Kavik, Sue Aikens hunts for caribou and ptarmigan on the tundra.

Alaskans pursue scarce resources in anticipation of the coming spring. In Kiwalik, Chip and Agnes Hailstone set up camp for future resource gathering. Andy's trip to his woodpile doesn't go as planned.

On the cusp of springtime, Alaskans encounter unexpected roadblocks in their struggle for survival. Glenn Villeneuve injures his foot while traveling in deep snow.

As winter comes to a close, Glenn hikes up a mountain to build a snow cave. Meanwhile, in Kiwalik, the Hailstones tow a sled load of meat and a broken snow machine back to Noorvik.

Our night train travels through the mystical midnight sun past the most diverse Norwegian landscapes. We meet people who want to restore the balance in nature in their own way.

Germany's Harz mountains stand for wild nature, with snowstorms in the winter and rain-soaked forests in the summer; filmmaker Uwe Anders travels to the Harz to capture both landscape and wildlife.

The source of the Vltava River lies in the Bohemian Forest; fed by cold and warm Vltava tributaries, Czechia's longest river flows through Sumava moorland and turns dark yellow like liquid gold.

Eastern Poland is one of Europe's last wild regions; the Biebrza lowlands make up the biggest national park in Poland and are of the utmost value for beavers, otters and countless aquatic birds.

Patrick investigates evolution's regenerative secrets; could the next major medical breakthroughs be hiding in deadly scorpions, prehistoric predators, or even the smallest animals on Earth?

Patrick goes in search of the animals that have mastered the art of protection; from invisible octopuses to invincible cockroaches, they inspire scientists to create new survival technologies.

Inspired by soaring albatross and venomous sidewinders - not to mention the fastest animal on land - Patrick discovers the secrets to cleaner, faster and farther travel.

Patrick investigates how we can restore Earth; from plastic pollution to ecosystem collapse, could mysterious squid, decorative spiders, or awkward bumblebees be a solution?

Chilli, Inara and their nine cubs meet and a standoff ensues; the mothers eventually part, but Chilli's cubs Siya and Kolisi mistakenly follow Inara.

Chilli has kept all cubs alive for a month since the separation; Inara courts Shadow and may be expecting; a hunt injures Chilli and Inara returns just in time but is seen as an outsider at first.

The mothers separate when Inara leaves with five cubs; she marches and hunts relentlessly to compensate for her eye but fails time and time again and is eventually forced to abandon the cubs.

Our night train travels through the mystical midnight sun past the most diverse Norwegian landscapes. We meet people who want to restore the balance in nature in their own way.

Germany's Harz mountains stand for wild nature, with snowstorms in the winter and rain-soaked forests in the summer; filmmaker Uwe Anders travels to the Harz to capture both landscape and wildlife.