2 January 2013 Last updated at 01:02

Giraffe fights and friendships revealed

As the tallest animals in the world, with gangly legs, twisting black tongues and patchwork markings, giraffes are instantly recognisable.

But we still know relatively little about the behaviour of these supposedly "gentle giants".

Footage recorded for a new landmark natural history series, Africa, coproduced by the BBC and Discovery, reveals a little seen brutal aspect to giraffes' lives.

Male giraffes were filmed engaging in a bruising fight, literally going head to head until a single giraffe is left standing.

Africa - a landmark

• Africa begins on BBC One on 2 January 2013 at 21.00GMT
• Watch and learn about the Kalahari, Savannah, Congo, Cape and Sahara

New research just published also shows that female giraffes form previously unrecognised close bonds with a select group of female companions.

Not only do they make "friends" in this way, they avoid other females they get on with less well.

Scientific studies of giraffes often focus on their iconic aspects: how fast they can travel or how high they can reach using their long legs, the strength of their necks and the colour of their coats.

But in recent years, biologists have turned their attention to the relationships between animals.

Although their tall height may make them conspicuous, it takes an expert to find giraffes in the desert.

The animals' home ranges extend up to 100 square miles as they seek out acacia trees in sparsely vegetated landscape.

"It took four weeks of waiting to capture about 60 seconds of fight," said Africa cameraman Martyn Colbeck, who described the sequence he filmed as "staggering".

See males fight with their famous necks as weapons

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The crew set up camp on the Hoanib River in the far north-west of Namibia with the aim of filming natural behaviour.

"[Guide and driver] Paul and I knew where we should be to stand the best chance of getting the most giraffes in the best location," Mr Colbeck told BBC Nature.

"We also knew that we would have to follow them all day, every day to stand a chance of getting a fight."

The filmmakers' "lucky break" came in the form of a female giraffe in oestrous: signalling her readiness to mate with any males in the vicinity.

Two males arrived competing for her attention. Their rivalry soon escalated into a physical fight.

"Paul and I have seen a lot of interesting animal behaviour in the remote deserts of Namibia, but neither of us had seen anything like this fight. And we are unlikely to see it ever again I suspect."

"Even though we were following the oestrous female and the consorting male, the fight came out of nowhere," he told BBC Nature.

The two challengers in the conflict were an older bull and a young male hoping to claim mating rights.

"Suddenly the challenger came around the corner of a bend in the river and immediately challenged the dominant male in the most brutal way," said Mr Colbeck.

In a giraffe fight, males stand side-by-side, pushing and shoving to judge which is strongest.

In evenly matched meetings, blows are sometimes exchanged - dealt by the giraffes' powerful, muscular necks.

The horn-like structures on the stop of the giraffes heads, called ossicones, can inflict injuries but, according to experts, fights rarely get this serious.

"Normally giraffes size each other up and after a bit of stand off and a few swings the fun is over," said Dr Julian Fennessy from the Giraffe Conservation Foundation, based in the UK and Namibia.

"When the battles are serious then it often ends in the subservient male skulking away. However, it can end in the death of one of them," he added.

In this exchange the loser only suffered a sore head after receiving a surprising knock-out blow.

Dr Fennessy told BBC Nature that such footage can help researchers understand more about this rarely witnessed behaviour.

"I am never surprised as we are only starting to learning more and more about giraffe behaviour as research on these iconic species is in its infancy," he said.

Namibia's "river of sand" is home to giraffes

This instinct for competition makes male giraffe naturally anti-social. But female giraffes do maintain close relationships with one another, according to a study published recently in the journal Animal Behaviour.

Early studies of giraffe societies suggested that groups were unstructured. But recent research has found that the animals demonstrate a dynamic common to chimpanzees, spider monkeys and spotted hyenas.

Scientists identified that individuals temporarily associate, resulting in fluctuating group sizes and membership.

To understand more about these short alliances, researchers observed animals in Etosha National Park, Namibia.

The team, from the University of Queensland, Australia, were able to identify individuals by their unique markings.

They found that females chose which members of a group they associated with and purposefully avoided others.

According to the biologists, this behaviour could be the result of overlapping feeding grounds and frequent meetings between animals.

Or it might be that female giraffes recognise each other from when they were young, and lived in giraffe crèches, or nursery groups, which have been widely documented in the wild, the researchers report.

However, males are much more solitary beasts, choosing to wander alone as soon as they reach adulthood.

If there are few mating opportunities, some studies suggest male giraffes do form "friendships" with one another.

But in the main, male giraffes prefer to be lone warriors.

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