Ingenious and cunning ways wildlife survives in a desert

Some of the most remarkable ways plants and animals have adapted to the world’s hottest and driest places were revealed during filming for Planet Earth II

Only a lucky few will have seen a golden mole, until now. Because these small, elusive mammals live beneath the sand and only come to the surface at night. That is why this footage captured by the Planet Earth II team in the Namib Desert is so compelling.

It was one of the highlights for Ed Charles, producer of the Deserts episode. “To have this incredible little animal give you very privileged access that not many people get was very special,” he says.

Despite their barren wasteland appearance, deserts are actually biologically rich habitats

And who could fail to fall in love with this ping pong ball-sized animal as it burrows through the dunes as if the sand was water. And as Charles explains, 'swimming' through sand with powerful legs and a wedge-shaped snout is just one of the ways the golden mole is superbly adapted to using the desert environment to its advantage.

In a world without light, this animal has lost its sight, instead relying on incredible hearing – its head acting like an amplifier. “It doesn’t hear in the conventional way like you and I do, its head has to be in contact with the sand, because the sand grains transmit sound through them,” Charles explains.

In this way it navigates and hunts with pinpoint accuracy.

Deserts, both hot and cold, cover about a third of our planet’s land area. They are tough and hostile places to live with very little rainfall – annual precipitation in a desert is generally less than 25cm. Despite their barren wasteland appearance, deserts are actually biologically rich habitats, full of animals and plants that have evolved to survive, and many cases thrive, over millions of years.

Temperatures can reach 50°C during the day in the hottest deserts – the key to survival is keeping cool and finding and preserving water. For many desert animals, like the golden mole, staying underground during the day where it’s slightly cooler, and coming out at night after the sun has gone down to forage, is an essential survival technique. Water is scarce and a precious life-saving commodity, and food can be very hard to find.

Other adaptations and strategies for surviving in deserts include dissipating heat through large body parts, retaining water by sweating and urinating less, and constantly moving from place to place to find supplies. Plants, such as the cacti of America, store water and protect it with spines.

These might seem quite obvious tactics for staying alive in such places. But the Planet Earth II team observed some superb and downright risky methods while filming in some of the most extreme places on Earth.

How to get water in a dry desert

The Namib Desert is the oldest desert in the world and also one of the most arid, with a meagre 10mm of rain per year on average. This almost completely barren landscape is too tough for most humans, yet there are species of darkling beetle, explains Charles, that have evolved an incredible skill – they can extract water out of thin air. Well, fog to be more precise.

And not only this, it has to be the right 'kind' of fog. At dawn, when this particular type of fog gets blown across the tops of the dunes from the Atlantic, and before it can be burnt away by the sun, these ingenious little beetles must scale impossibly large dunes to reach the top. Here, they stand with their heads down and bottoms up facing into the breeze. Minute water droplets in the fog then stick to bumps on the wing cases, and when they eventually become large enough, the droplets roll down channels and into the beetles’ mouths.

“How these beetles learnt how to do this in the first place is just a mystery and really incredible,” Charles says.

This ingenious adaptation has provided researchers with the inspiration for technologies such as self-filling water bottles, which draw moisture from the air of coastal deserts for human consumption.

But what do you do if you’re helpless and incapable of getting life-saving water? That’s the perilous situation that faces newly hatched sandgrouse chicks, which were laid in a scrape in the heart of an arid, barren wasteland. There are few predators to trouble them here, but living in these scorched lands is a risky strategy, because without water the little chicks will soon die.

It’s an ingenious solution to desert living and the only bird in the world that can do this

So it’s the males to the rescue. They travel en-masse to watering holes, sometimes up to 60 miles away, and here’s the ingenious bit, their breast feathers are specially adapted with a larger number of tiny barbs than normal feathers, which soak up water like a sponge. Absorbing about 20ml – that's roughly a quarter of their body weight – of water into their feathers, they then make the long return journey to the chicks. They do it every day for two months, until the chicks can make the flight themselves.

“It seems like an incredibly brutal start to life, but provided they can get water, it gives them the best chance of making it to fledging.

“It’s an ingenious solution to desert living and the only bird in the world that can do this,” says Charles.

Food is important too

Water is one of the key resources needed for life and animals that live in deserts have incredible ways of obtaining and retaining it. But man, and most animals, can’t survive on water alone; they also need to find food. And that can require a range of different, but no less ingenious strategies and adaptations.

Take the shrikes for example, a family of birds that take advantage of the spines and thorns that some desert plants use to protect their water stores, and do something rather clever with them. They impale small mammals and large insects onto them.

You expect something like that from a monstrous predator, but then this rather beautiful little songbird pops into frame

They do it for two reasons, explains Charles. During breeding season the male is showing how virile and what a good hunter he is. Secondly, they don’t have to hunt everyday if there is a larder stocked with ready meals that can be fed to hungry chicks.

It’s an ingenious solution to keeping your young alive during the leaner times when food is scarce, as it so often is in these challenging places.

“It’s almost like a Christmas tree festooned with carcasses, rather than baubles and tinsel.

"There’s all these dead things, some with their head ripped off... You expect something like that from a monstrous predator, but then this rather beautiful little songbird pops into frame,” Charles says.

The most extraordinary behaviour for the producer, however, was the story of a little bat taking on a deadly scorpion. It revealed the risks some animals will take to get a meal, and the benefits to be gained if successful. They filmed, for the first time, a desert long-eared bat taking on deathstalker scorpions on the sands of the Negev desert in Israel.

These scorpions are some of the most dangerous in the world, with formidable pincers and a venomous sting that contains a very powerful mixture of neurotoxins, which would seriously trouble a healthy human if stung. But these bats were observed hunting and eating scorpions at night and despite being stung several times, still got their meal.

There are a lot of scorpions in the desert, explains Charles, so if you can work out how to hunt and kill them, you’ve got it made. They are taking advantage of one of the few readily available food sources, when very few others can.

“It’s incredible that they’ve adapted to do this, but what’s even more incredible is that they seem to be immune to the venom as [the bats] simply weren’t dying.

“It’s a brutal battle these bats undertake just to get a meal, but they choose to do it because desert living is so tough, they have to do it,” he adds.

These are just a few of the resourceful strategies that have evolved over millions of years for surviving in the world’s hottest and driest places, where most humans fear to tread.

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

Jeremy Coles is a staff writer for BBC Earth. He is @jpcoles on Twitter.

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