Winter has begun and with less solar energy the northern hemisphere freezes, life is at its hardest; as the planet starts its incredible journey around the sun, Earth's northern pole tilts away from the warmth and light.

Spring is the season of opportunity; the great melt begins and new life erupts; life in the Southern Hemisphere gets rough with worsening conditions as animals prepare for shorter days.

Summer is the season of extremes. By June, the top of the planet is 24 hours of sunlight, while the south is frozen in darkness. Whilst for the northern hemisphere this is a season of plenty, much of the south will face famine, fire and torrential rain.

Autumn is the season of change, offering new beginnings or a chance to take a new path; many species prepare for winter to secure their place for the next year's circle of life.

A newly-hatched penguin chick grows a coat.

Scientists, community members and conservationists uncover new behavior, use pioneering and inventive techniques and put their lives on the line to protect the animals that roam the earth.