David Attenborough’s life lessons

For 60 years, David Attenborough has should us that nature is neither ‘for us’ nor ‘against us’ – it just is! But we need to learn from nature – lest we lost it by endangering the Earth!   

What wisdom springs to mind when you think of the natural world?

From the basics of never saying boo to a goose right through to reconstructing prehistoric giants, one man has been guiding TV audiences through nature’s biological maze for 60 years.

During this time Sir David Attenborough has dedicated himself to bringing science to the small screen, introducing us to parts of the natural world that had never been seen before.

Along the way, he has learned a great deal and here we share a few of the lessons from his incredible career so far.

Predator or potty?

In the 1990s scientists believed the pitcher plant Nepenthes rajah, found in the rainforests of Borneo, gained nitrogen by consuming the bodies of rodents after a tree shrew was found inside the plant’s pitcher-like cavity.

Experts believed the rodent had been tempted there by the carnivorous plant’s nectar before falling to its watery grave.

Sir David shared this information with fascinated audiences in The Private Life of Plants series. But skip ahead 15 years and new evidence suggested a very different explanation.

In this video clip, Sir David describes how the mystery was unravelled.

Researchers from Monash University, Australia, found that the tree shrews were indeed tempted to the plants by nectar, but were not the plant’s prey.

Instead, the mammals were filmed using the pitcher plants as toilets, leaving their nitrogen-rich droppings in the plant’s fluid-filled orifice.

“Most carnivorous plants seek nitrogen and nutrients hard to obtain from their environment so it’s logical that some should specialise in droppings, although animals being trapped is more usual,” explained Dr Martin Cheek, a Nepenthes specialist from the Royal Botanical Gardens, Kew.

The species was first discovered in 1859 and according to Dr Cheek it has a number of relatives in Borneo that may gain nitrogen in the same way.

“They all have the large pitchers with the pitcher lid presented at the same angle as in Nepenthes rajah that seems to suit the shrews licking the lids, which is thought to stimulate defaecation,” he explained.

Dragon’s deadly kiss

Komodo dragonThe dragon’s bite is far from myth

One of Sir Attenborough‘s most memorable early encounters was with a komodo dragon on the series Zoo Quest for a Dragon. He was lucky to find one on the mission for London Zoo, broadcast in 1956.

But at the time the plucky crew had no idea just how dangerous the dragons were. It was more than 50 years later that scientists revealed the reptiles had a deadly secret weapon: venomous saliva.

Previously, biologists had thought that the dragons killed large prey with “dirty” mouths. Water buffalo were thought to succumb due to the harmful bacteria present in the reptiles’ mouths, flooding wounds inflicted by the lizards with microbes and eventually causing blood poisoning.

But venom expert Dr Bryan Fry from the University of Melbourne, Australia suspected something else after identifying that lace monitors, close relatives of Indonesia’s infamous dragons, had venomous saliva.

Sir David shared the secret of the world’s largest venomous reptile in the series Life and since then Dr Fry has continued to analyse their fearsome feeding method in detail.

“The role of the venom is to exaggerate the blood loss and shock-inducing mechanical damage caused by the bite,” said Dr Fry who described the reptiles as possessing an “arsenal of weapons” to use when hunting feral pigs, deer and water buffalo on the island.

He has since found that the dragons wound their prey with a devastating “grip and rip” technique and is now investigating the reptiles’ environment to understand where the initial bacteria theory came from.

“The sampling of komodo mouths that purported to show them harbouring pathogenic bacteria neglected to sample the real source of any infection to the water buffalo – the faeces-filled watering hole the dragons recently drank from,” he explained.

“We are hot on the heels of what kind of bacteria in the water actually cause the infection of the buffalo when it does occur.”

Avian affairs

Until the 1960s certain species of birds were upheld as examples of monogamy in the natural world. But through further investigation, ornithologists found that species previously considered ‘loyal’ were actually playing away.

The development of DNA techniques provided unequivocal evidence that females in seemingly monogamous pairs would occasionally pair off with a different male to mate.

In 1998, Sir Attenborough highlighted the infidelity of female hedge sparrows and since then so-called “affairs” have been recorded in 80% of all bird species studied.

Ornithological reproduction expert Prof Tim Birkhead of Sheffield University suggests it was a change in human perspectives that opened the doors for these discoveries.

DunnockHedge sparrows, or dunnocks, are now renowned for their varied sex lives

“Observations of avian infidelity go back to the 1950s; their significance wasn’t appreciated until the late 1960s, 1970s when our view of evolution changed and became more focussed on individuals,” he told BBC Nature.

Scientists are now studying the motivation behind this behaviour. Although males clearly benefit from this opportunistic mating, the benefits for females are yet to be fully understood.

“The latest or most persistent mystery is why females bother. We don’t know what they get out of it,” said Prof Birkhead.

Snake backstabbers

In the 2008 series Life in Cold Blood Sir David and colleagues set out to lift the lid on the world of reptiles and amphibians.

The team visited New York state and filmed a memorable sequence of anunsuspecting mouse being bitten by a timber rattlesnake in the dead of night.

The footage captured has since been painstakingly analysed by researchers, frame-by-frame, to explain striking behaviour in wild snakes.

This summer, assistant Prof Rulon Clarke and colleagues from San Diego State University, California, US published their results which suggest that rattlesnakes only strike at prey once it has passed them.

“In laboratory experiments, snakes rarely miss their prey. But in the wild, interaction between snakes and their prey is much more complicated,” explained Prof Clarke.

Timber rattlesnakeThe timing of a timber rattlesnake’s strike is crucial

He told BBC Nature that in the wild, if the snake is too far away from its target, its prey will perform evasive dodges to stay safe.

“For this reason, snakes seem to time their strikes so that they are striking at prey when it is very close, but also when it is moving away,” he said.

The team’s observations explain why snake bites are found on the flank of prey.

“Without recording the snakes in the wild, we would have no real idea of how difficult it is for them to actually land a strike on a free-ranging prey item, subject to all the vagaries of the natural environment.”

One thing is common to all of these lessons; learning is an ongoing process.

What we know now could be considered ridiculous, old-fashioned or basic in another 60 years but as long as discoveries are shared in rich detail they inspire further investigation by others.

Attenborough: 60 Years in the Wild begins at 2100 on BBC Two, Friday 16 November.

Join BBC Nature on Facebook and Twitter @BBCNature.

Source : http://www.bbc.co.uk/nature/20273855

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2 thoughts on “David Attenborough’s life lessons

  1. Pingback: The Story of Us « Nature and Us

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