From large lions to a tiny harvest mouse, Planet Earth II reveals how the lives of so many animals are entirely shaped by the fickle fortunes of grasslands

The hilarious dance of the male Jackson’s widowbird (Euplectes jacksoni) as he jumps above tall grasses in West Africa is one of the many memorable moments from Planet Earth II. For Chadden Hunter, the producer of the Grassland episode, it is also a perfect example of how the lives of these birds are inextricably linked to the grasslands in which they live.

“Grass is a 'Lazarus' plant: it can endure flooding, frost, and even fire," explains Hunter. “It’s a miraculous survivor, and we wanted to show how the lives of so many animals are shaped by the fickle fortunes of grass.”

 

Many grassland animals lead nomadic lifestyles, following the cycle of growth and abundance in an area before moving on for pastures new once drought or destruction takes hold. The Jackson’s widowbird is no exception, seeking fresh new growth not just for food, but also as a means to secure a mate.

Males establish courting arenas by either nipping off or treading down grass stems to create a flattened circle with a single tuft in the centre. Being no larger than the size of a blackbird, however, means that the females would struggle to find these tiny 'dancefloors’ from within the vast swathes. So to advertise their whereabouts the males must jump up to a metre high, repeatedly, in a seemingly comical and peculiar dance. Not only does it reveal their location to potential admirers, it is also a display of their stamina – a bird that can sustain this dance is what catches a female's eye.

A miracle plant

The family of grasses covers a quarter of all land on Earth, which in turn supports and sustains more large animals than any other habitat. Named after its most famous inhabitant, the elephant grass of north east India is one of the tallest, reaching heights of up to four metres. “Elephants will push their way through creating a temporary network of beautifully carved tunnels, like Alice in Wonderland,” explains Hunter.

Grasses, unlike most other plants, have evolved to grow not from their tips but from closer to their roots, making them almost indestructible. While the perfect fodder for animals, their ingenious growth strategy enables them to rapidly bounce back from even the most intense grazing. This ‘shoot from the roots’ attribute also allows them to survive fires, freezing temperatures, drought, and even flooding.

Swamp cats

In southern Africa, the Planet Earth II team filmed the flooding of one of the most remarkable grasslands on Earth. Every year, distant rains in the Angolan highlands pour down into Botswana, transforming over 12,000 square km of grassland habitat into a swamp. This serious inundation would cause many plants to be quite literally ‘swamped’, but grasses grow so fast that their leaves are able to simply rise up above the water and into the sunlight.

Cape buffalo (Syncerus caffer) time their arrival in their thousands to feed on this annual growth bonanza, which attracts the attention of the local lions that are keen to take advantage. “Lions hate getting wet, but these prides have learnt to use the water’s edge to their advantage.

"They are one of the only prides in the world that have learnt how to do this, making them locally known as swamp cats,” explains Hunter.

Spending a total of five months over a two year period in the remotest parts of the Okavango Delta, the team dodged hippos and crocodiles and even had their filming vehicle flipped over by elephants – luckily while they weren’t in it – to capture a pride of lions tackling buffalo in these most challenging of conditions.

A bountiful harvest

Natural grasslands tend to occur where rainfall is too sporadic for forests to grow. However when our landscapes are governed by agriculture, grasses will also tend to dominate.

It’s so rare on a production of this scale that we actually have the opportunity to film in the UK

In summer, ancient English meadows become the miniature equivalent of fruiting forests for the local harvest mice (Micromys minutus), which must climb into the canopy to gather seeds. The Planet Earth II team were also keen to champion this diminutive little mammal. “She stole all our hearts” admits Hunter.

"Meadowlands are more biodiverse per metre square than tropical rainforests.

"And it’s so rare on a production of this scale that we actually have the opportunity to film in the UK, making this shoot very special."

And who could fail to fall in love with Britain’s smallest rodent as she swings through the stems using her prehensile tail as a fifth limb. Her tail measures the same length of her head and body combined, allowing her to navigate the stems of grass, thistle and bramble, much like a spider monkey moving through the Amazon jungle.

Enduring the cold

Being so ruthlessly adaptable enables grasses to dominate large swathes of our planet, all the way from the baking Equator to the freezing Arctic Circle. As winter approaches, the prairies of North America begin to freeze, but the ubiquitous grasses still continue to play a pivotal role in the survival of the bison here.

During the lazy days of summer bison are easily able to access the lush green shoots, but as the temperatures plummet, a metre of snow can make uncovering their food decidedly more difficult. So each bison will need to effectively turn into a snow plough, bull-dozing away up to five tonnes each day in order reach to reach the withered, yet nutritious grass stems below.

Even with thick coats that can help insulate the bison at temperatures of -30°C, Hunter explains their dependency on the hidden grass: "They must chomp on this dead grass, just to get them through. In a bad winter a third of the herd can die from starvation."

Like all grassland inhabitants, the bison are at the mercy of these unpredictable lands. As grass has crept its way across our planet, it has come to dominate the lives of so many animals, who must adapt to its fickle fortunes in many remarkable ways.

UK viewers can tune in to Planet Earth II, which continues on BBC One this Sunday at 20:00 GMT.

Be the first to know about new BBC Earth articles and wildlife programmes by signing up for the BBC's new personalised email newsletter here. You can also follow BBC Earth on Twitter and Instagram and like us on Facebook.