Barking deer

The barking deer (Muntiacus muntjak) is a small species of deer native to Southeast Asia.

Earth-Touch filmed a female barking deer, probably pregnant, in the Khao Yai National Park in Thailand (Deer search for fresh shoots).

Named after its barking alarm call, the deer can reach a height of 50 to 75cm (20 to 30in) and weighs just 25kg (55lb) or so.

Males have short antlers which extend from two bony outgrowths or pedicels on the skull. They also have two long canines, or tusks, in their upper jaws which they use for fighting.

Barking deer live mostly alone and rarely are more than two of them seen together.

Image © Earth-Touch 2008

Did you know? Ragged-tooth shark

The most obvious distinguishing feature of the spotted ragged-tooth shark (Carcharias taurus, also known as the grey nurseshark or sandtiger) must be its impressive set of teeth. There are around 44-48 upper teeth and 41-46 lower teeth. The shark is constantly replacing its older teeth with new ones. A ragged-tooth shark can go through around 30 000 teeth in its lifetime.

These needle-like teeth are used to catch a diet of bony fish, squid, eels, rays and crustaceans.

Earth-Touch has recently been filming a group of pregnant ragged-tooth sharks at Sodwana Bay, part of the Isimangaliso Wetland Park on the Indian Ocean coast of South Africa. Links to the video clips are found below.

These sharks are very social animals and more often than not they are seen quietly floating around in large groups. In spite of its fierce appearance the ragged-tooth shark is not aggressive at all unless provoked. In fact during the gestation period the female shark avoids encounters with humans.

This population has a migratory breeding pattern which starts with the movement of sardine shoals from South Africa’s Eastern Cape coast northwards to the KwaZulu-Natal coast. Here the sharks mate, then the females move northwards again to the Sodwana Bay area for part of the gestation period before returning to the Eastern Cape to give birth.

Ragged-tooth sharks are ovoviviparous reproducers. What this means is that the female produces eggs which, when fertilized, hatch inside her. These eggs have no placental connection to the female. The largest embryo develops teeth and feeds off the smaller embryos during the gestation period. The pup that survives to be born typically measures in at around 100cm in length. Only one pup is born from each of the two uteri.

Unsurprisingly, ragged-tooth sharks have no natural predators to speak of. Like most sharks, they do not have particularly good eyesight. They tend to rely much more on their sixth sense, which is electroreception. Small, sensitive pores located under their noses allow the shark to detect any small electric current in the water.

Another interesting feature of this species is that it gulps air at the surface to improve its buoyancy.

See pregnant “raggies” in the clips:

Pregnant sharks hug the reef

Sharks relax around boulders

Sharks in a surging sea

Sharks lounge at the reef

Sharks follow a path

Image © Earth-Touch 2008

Into the future with a ping

Can you imagine my alarm when I was recently informed that I would have to know how to “ping” a satellite as part of my job description?

My friends know that if it was left to me to invent the wheel, for example, humankind would have to wait for many more centuries. I am one of those people who are good at using technologies once I have been given the “know-how”. But I’m not good at inventing anything myself, nor do I have the patience to spend hoursworking out how to engage these systems.

So I was relieved to hear that I would be trained and equipped with the skills to do the pinging.

Our company, Earth-Touch.com, is in the communications business – specifically creating wildlife and natural sciences content. We have innovated and introduced ground-breaking methods for the acquisition and distribution of Web-based media as well as HD (high definition) content for electronic broadcasting. To facilitate this and become world leaders, we have absorbed exciting new technologies and disciplines.

Our intention is to provide world-class communication in our field. And to achieve these aims, all company staff will be involved in an intense process of acquiring relevant technical knowledge and skills.

Many of the current employees were previously involved with various aspects of traditional media or formal film-making.

Against this background we enter the “new media” era. Basic satellite technology and pinging will be just one of the many new skill sets required for creating and delivering our content to an international audience. We mean business.

So, the Ping 101 course or the Idiot’s Guide to Pinging will soon be a welcome intervention in my life. I am signing up for this and any other course that will launch me and my colleagues into the 21st century and beyond.

– by Pierre Minnie, Earth-Touch crew

Images © Earth-Touch 2008

International Year of the Reef

The International Coral Reef Initiative (ICRI) has designated 2008 the International Year of the Reef.

Earth-Touch has published high-definition video footage filmed at several reef locations in the past year. Users can explore this underwater treasure trove by following these links:

Indian Ocean, KwaZulu-Natal, South Africa:
See lobsters, eel and paperfish in Amazing creatures flit about the red coral forest.
It takes many years for a coral tree to grow this big.
Did you know that blue parrotfish exude slime as they sleep?

Indian Ocean, Mozambique:
A reef surface is densely packed with coral and sponges.
A Gorgonian fan is an ecosystem in itself.
Wire coral and sea fans add to the diversity of the reef.

Image © Earth-Touch 2008

Fledglings prepare for flight

Yellow-billed kites (Milvus migrans parasitus) are opportunistic feeders. They glide through the air, scanning the ground for carcasses of dead animals, or for small live prey such as lizards, locusts and frogs.

The adult kite that Earth-Touch has been tracking attends to its chicks’ needs, but soon it will be vital for these young fledglings to learn the ultimate survival skill, flight.

Earth-Touch has filmed footage of the chicks’ development as it unfolds in nature.

The typical “nest-bound” period for the yellow-billed kite is four to eight weeks, during which time the young kite will gradually build up its confidence.

During the latter stages of this period, the young birds begin to test their wings by flapping them against the wind, without actually leaving the nest. This signals that the young kite is preparing to finally embark on its first flight.

They will typically begin by flying to branches that are in close proximity to both the nest and the watchful eye of the parent bird. Once they have mastered this, they will begin to venture further out, skilfully steering themselves through the air.

Image © Earth-Touch 2008

Cleaning stations of the sea

In the Earth-Touch clip, Carpet of devil firefish, fish and eels take shelter in caves and small overhangs at the reef in Ponta Malongane Bay, southern Mozambique, in order to get cleaned.

In these crevices these fish are seen allowing small cleaner shrimps and wrasses to pick off parasites and dead or infected skin.

This provides food for the shrimps and wrasses. Their relationship with the fish and eels is therefore mutually beneficial or symbiotic.

Image © Earth-Touch 2008

First find your turtle

I had grand visions of all the turtles I was going to find and film for Earth-Touch in southern Mozambique. I’d decided to walk a 5km (3mi) stretch every night and guessed that, according to the law of averages, I’d be onto an egg-laying leatherback or loggerhead turtle every three nights.

This delusion quickly blew away into the clammy northeast wind that scoured the beach every night. The novelty of walking with the camera, LED light and lead acid battery strapped onto my back wore off rather fast.

The final straw was the discovery of a fresh turtle nest directly in the access path near our campsite – on our return from the 10km (6mi) route march one night.

I then decided to unleash my secret weapon.

I’d carted my mountain bike along to the campsite for this purpose, figuring I could cover a lot more ground that way than on foot.

As with many plans hatched at the office desk, it wasn’t that practical. Peddling furiously into the 30km/h (19mph) wind while negotiating drifts of soft sand in the black of night actually verged on the comical. It was Walter Mitty meets John Cleese on safari.

I’d given up, content to work exclusively underwater for our Earth-Touch stories (see, for example, Pregnant sharks hug the reef, Swimming amongst seals, Close encounter with a leviathan and Encounter with a big fish), when a tall, lanky character arrived at Ponta Malongane. Pierre Lombard to the rescue.

Pierre’s been working on turtles in this area for many years, and his tagging and research programme has the sanction of the Mozambique government.

He took us along in the vehicle he used to find and tag turtles on the beach every night. This was a breeze, sitting inside the warm capsule, barrelling along the inky black beach until the telltale pattern in the sand gave away a turtle further up the sand, looking for a nesting site.

The first night we spent with Pierre resulted in seven turtle sightings. I stayed with one of these for the duration of the nesting process (see the Earth-Touch clip, Loggerhead turtle lays her eggs). At first I wasn’t able to use any light for fear of scaring the animal off, so I just sat a foot or two away from the loggerhead as she dug.

This experience matches anything I’ve ever done, sitting listening to the sound of the waves and the big turtle heaving in breath after breath as she shovelled sand in the darkness. It prepared me for filming the egg-laying process in the best possible way.

– by Graeme Duane, Earth-Touch crew

Image © Earth-Touch 2008

Did you know? Oxpeckers on the back of mammals

Oxpeckers are often seen on the backs of animals like hippo, buffalo and kudu. They feed off parasites such as ticks and bloodsucking flies that live on the mammal’s skin.

These birds have a mutual relationship with mammals, removing parasites in exchange for observing the surroundings from an aerial viewpoint and alerting them of danger.

However, the significance of their impact on the mass of parasites is often questioned.

Mammals often have to rid themselves of excess parasites through other means such as grooming, bathing in mud, rolling in sand or rubbing their bodies on nearby trees.

Nevertheless oxpeckers are adapted to remain balanced and move about on the skin or hair of their hosts as they feed.

These birds are not found on elephants, perhaps because their skin differs from that of other mammals and they do not have many ticks. Oxpeckers are a nuisance to elephants, which are often seen swatting these birds off them with their tail, trunk or ears.

Oxpeckers are not the only birds that frequent the backs of mammals. Another is the cattle egret, which eats prey disturbed by the mammal and sometimes eats parasites on the mammal.

See birds on the backs of various mammals in the Earth-Touch clips, Hippo bull shows his dominance, Frog chorus, Sea of black buffalo and Silent sentinels.

Image of red-billed oxpecker on a hippo's back © Earth-Touch 2008

The week’s most viewed stories

The most popular stories on Earth-Touch in the past week (from Friday 18 January to Thursday 24 January 2008) were:

Number 1

Baboons in leadwood tree

Alert males keep watch, while others play and rest in the treetops.

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Number 2

Crowd of Zambezi sharks

These predators patrol the waters constantly, looming powerfully into view with a steely sheen.

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Number 3

Fish defend nest

A breeding pair of bluespotted chromis sweep their territory.

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All images © Earth-Touch 2008

Caterpillars trick ants

When humans make themselves smell more alluring than they really are it’s fairly harmless, but it’s a case of life and death for the larvae of Alcon blue butterflies, which trick red ants into feeding them, leaving the young ants to starve.

Alcon caterpillars dupe the ants by giving off a scent which mimics that of the insects’ own larvae.

This phenomenon, which was recently detailed by BBC News, is being studied in Denmark, one of the last strongholds of the near-threatened Alcon blue (Maculinea alcon).

“The caterpillars first start developing on a food plant but after they reach a certain stage, they leave the plant and wait on the ground to be discovered by these ants,” explains Dr David Nash of the University of Copenhagen.

“They mimic the surface chemicals that the ants have on their own brood, and we’ve been able to show that the closer that mimicry, the faster they get picked up by ants,” he says. When the caterpillar matures it leaves the ant nest.

The ant hosts (Myrmica rubra and Myrmica ruginodis) can develop resistance against this exploitation by changing how they smell. But this only works when ants living close to the caterpillars’ initial food plant, the rare marsh gentian (Gentiana pneumonanthe), do not interbreed with ants from sites where the plant does not occur.

Scientists say a fuller understanding of the relationship between such ants and caterpillars is needed to help protect the Alcon blue, which is an important indicator of the health of moist-grassland ecosystems in Europe.

Images © David Nash

Hippos in dark water

Darkness is falling and a pod of hippos in the Blyde River, in South Africa, is just visible as their nostrils and the ridges over their eyes protrude above the water.

The dominant bull holds sway over the group of females and younger animals, but his authority is beginning to be challenged by a younger male. There could be a clash in future.

Watch these prehistoric-looking creatures in the Earth-Touch clip Calm before the battle.

Image © Earth-Touch 2008

Did you know? Clownfish

Clownfish, their vibrant colour making them distinctly visible, live amongst sea anemones, immune to their stinging tentacles.

A layer of mucus on their body is their protection from these stings, which are fatal for other fish species.

The clownfish is a highly territorial fish, fiercely guarding its anemone home from predators and rivals.

Anemones are believed to avoid stinging fish that have gained shelter for a while, so they do sting some new clownfish.

See two twobar clownfish (Amphiprion allardi) swimming in and out of their anemone home in the Earth-Touch clip, Fish take refuge from ocean surge

Image © Earth-Touch 2008

Capturing spirit of place

Guest Blog By Diane Hossick

Back in the 1970s, the novelist Lawrence Durrell (brother of naturalist Gerald Durrell) presented a memorable BBC TV series entitled Spirit of Place. Beautifully shot, it matched Durrell’s inimitable use of language with landscape, flora, fauna, and people, focusing on European and North African places of great beauty: towns, villages, coast and countryside.

The notion of spirit of place is one that has stayed with me ever since. What is it about a particular place that makes it unforgettable, leaving an indelible mark on your heart and your mind? It differs, I suppose, depending upon the location. The spirit that one senses in a fine city, such as Venice, is not what one senses in a wilderness. In a beautiful city, we are awed by the achievements of those who created it. We are struck by line, structure, vista and the way that people use and relate to the buildings that surround them and in which they live and work. In a wilderness, in the wild, a different feeling is at work – perhaps it is the very absence of human beings, the absence of constructed things, that we marvel at. Of life continuing as it has for aeons, without any interference from human beings.

Standing on top of a ridge looking down across a vast plain in Southern Africa, I experienced a deep awareness of the absence of human beings, of a landscape that had taken millions of years to evolve to this point. And of a landscape inhabited, to a greater extent, by animals, insects, birds and plant life.

Of all the places I have visited in the 50 years that have passed since I first set foot outside England, I can’t think of anywhere where the land spoke to me in the way that it did in Africa. Whether it was lying in bed at night in a wooden house in the Tsitsikamma Forest, listening to monkeys crashing across the roof and sending the dogs into a frenzy; pushing through brush to reach the edge of a cliff top, smelling the fynbos, and looking down on the aquamarine Indian Ocean below; driving through the bush and pulling to a quiet halt to catch sight of the first kudu, the first zebra.

And this is why I respect what Earth-Touch is doing, recording and sharing awesome moments of life on earth and in the sea. We know that greed and avarice are causing enormous and probably irreparable damage to our fragile planet. I have been fortunate to see as many wonderful places as I have but, these days, I am conscious that globetrotting comes at a price. Now I try only to travel with a purpose. I know too that, even with a purpose, my travelling days are not infinite. I will age, as the earth ages, and although I have every intention of remaining fit and well for as long as I possibly can, I have no idea what the future may hold.

I believe that Earth-Touch’s work will become increasingly important not just for now – for young people and old – but for future generations, using the wizardry of technology to bring us the story of our natural inheritance. And reminding us that we squander that natural inheritance at our peril.

Visit Diane’s blog: www.60goingon16.typepad.com

Touchy subjects

Sodwana Bay in summer means one thing for me: ragged-tooth sharks in clear blue water. In mid to late summer, females settle on some of the Maputaland reefs for their gestation period.

They are among my favourite subjects, but it’s not without difficulty that we get decent footage of their behaviour. During this gestation period, the animals go into self-preservation mode and are very shy and difficult to approach. When we dive on scuba they flee to the edge of our visibility.

The only solution is to take a really deep breath and freedive down to the bottom to wait for the approach of one or two of the raggies.

If the timing is right, one will even swim right over you. We’ve had to lie on our backs at times to let the shark trundle over us undisturbed.

An obvious conclusion is that these animals are very susceptible to diver pressure. This may be one of the reasons we’ve seen dwindling numbers at areas like Raggie Cave at Aliwal Shoal on the KwaZulu-Natal coast. The sharks just don’t like groups of scuba divers following them around.

See these raggies swimming in Aliwal Shoal in the Earth-Touch clip, Lone 'raggie' lies in wait

– by Graeme Duane, Earth-Touch crew

Image © Earth-Touch 2008

Did you know? Indian Ocean bottlenose dolphins

One of the most common species sighted off the eastern coast of Southern Africa is the Indian Ocean bottlenose dolphin (Tursiops aduncus), which lives in pods of sometimes 100 or more animals.

Like whales, dolphins are cetaceans whose ancestors were land-dwelling animals.

The Indian Ocean bottlenose dolphin has been recognised as a species separate from the common bottlenose dolphin (Tursiops truncatus) only in the past few years.

Because these dolphins favour in-shore waters, their long-term survival is threatened by human activity, including the setting of shark nets to protect swimming beaches, in which the dolphins are sometimes caught.

In the clip Dolphin encounter, Earth-Touch crew member Graeme Duane swims amongst a pod of about 50 bottlenose dolphins off Techobanini Bay, southern Mozambique.

Image © Earth-Touch 2008

Did you know? Tsessebe

Tsessebe (Damaliscus lunatus) are highly territorial antelope. Males regularly patrol and mark their range.

They secrete a sticky fluid from their preorbital glands onto grass stems, or rub their faces and horns on anthills and sandy mounds.

They also have glands on their front feet and will paw the ground to mark it with their scent.

Tsessebe are often seen standing on mounds, showing their presence to deter potential trespassers.

See this grazer in the Earth-Touch clip, Dominant tsessebe chases challenger.

Image © Earth-Touch 2008

The snow hunter

The great grey owl (Strix nebulosa) is one the largest in the world and in North America it is the tallest owl with the largest wingspan. Yet there are other owls that weigh more and have bigger feet.

This bird is grey and has yellow eyes, a round head and no ear tufts. It has black and white markings under the face which resemble a bowtie.

Although largely nocturnal and active at dusk and just before dawn, it is sometimes seen in the day, as in the Earth-Touch clip Great grey owl spotted in daytime. It is sometimes out and about in the daytime during the breeding season.

The species is also commonly called the great grey ghost, phantom of the north, cinereous owl, spectral owl, Lapland owl, spruce owl, bearded owl and sooty owl.

When hunting in winter, these owls plunge into snow to get at their prey (mostly small rodents) and have the power to break a thick snow crust with their talons. This capability gives great grey owls an advantage over other predatory birds, which must hunt in areas where there is lighter snow and the prey is more accessible.

Image © Earth-Touch 2008

Grace under pressure

The trumpeter swan is the largest and rarest swan in the world. It is a magnificent bird with white feathers and a black bill, feet and legs.

In the 19th century they were nearly extinct but through conservation efforts today there are more than 6000 of them in North America.

These birds establish life-long relationships at about three years old and nest the following year.

Trumpeter swans have a loud, echoing, trumpet-like call, hence the name.

Watch this beautiful species in the Earth-Touch clip Rare swan on the lake.

Image © Earth-Touch 2008

Elephant bulls browse

In the Earth-Touch clip, Elephant bulls follow new growth, a young and an older elephant bull move along a tree line in the Okavango Delta, Botswana, feeding as they go.

There has been some rain in the area. As the pans begin to fill with water, animals disperse over a wider area. Drier places now have new grass for the animals to eat, and this grass has more nutrients than grass in the wetter parts of the delta.

Elephants need to spend 16 to 18 hours a day feeding. Bulls like the ones in this clip eat as much as 270kg (595lb) of food a day.

Image © Earth-Touch 2007

Did you know? Tamandua

There are two species of tamandua, the northern (Tamandua mexicana) and the southern (Tamandua tetradactyla).

These anteaters are found in Central and South America.

The northern tamandua has a distinct “v” marking on its back which occurs only in some southern tamanduas.

The animals have four digits on their front feet and five on their hind feet. They walk on the outer edge of their forepaws so as not to cut themselves with their sharp claws.

Tamanduas spend most of their time in trees and feed mainly on arboreal termites and ants. They hunt these by ripping open nests with their strong limbs, then sticking their long snout into the nest and using their long, sticky tongue to grab the insects. As they have no teeth, tamanduas digest their food with their powerful gizzard, an internal organ that grinds up food.

See a tamandua found in the Pantanal region of Brazil in the Earth-Touch expedition footage, Anteater takes cover in tree roots.

Image © Earth-Touch 2008

The week's most viewed stories

The most popular stories on Earth-Touch in the past week (from Friday 11 January to Thursday 17 January 2008) were:

Number 1

Crowd of Zambezi sharks

These predators patrol the waters constantly, looming powerfully into view with a steely sheen.

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Number 2

Masters of the sneak

Zambezi sharks swim close to the lens, as their activity heightens ahead of the arrival of a cold front.

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Number 3

Python eyes a nearby cormorant

A beautifully marked young python spots a potential meal from its perch high up in a fig tree.

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All images © Earth-Touch 2008

Three new salamander species found

Scientists have made a thrilling discovery of three new species of salamander in a remote forest reserve in Costa Rica. Two of the species are nocturnal, belonging to the Bolitoglossa genus, while the third is a dwarf variety from the Nototriton family, growing to little longer than a thumbnail. The three new finds bring the number of Costa Rican salamanders known to science to a total of 43.

“Discovering so many new species in one area is exciting, particularly as this is probably the only place in the world you can find these animals,” said Dr Alex Monro of London’s Natural History Museum, who is leading the project.

Scientists believe the region is a centre for diversity for these tailed amphibians. It is thought to be home to some two-thirds of all Costa Rica’s native species, including hundreds of birds, mammals, reptiles and other amphibians, and thousands of plants.

Shy and elusive, salamanders look a lot like lizards but have smooth, delicate skin instead of scales. These creatures are descendants of the first land-dwelling vertebrates, with the earliest known true salamanders recorded to have lived about 150-million years ago. Today there are about 380 different species of salamander belonging to 10 different families.

Many salamanders inhabit moist, forested areas, sheltering in shallow burrows or among fallen leaves and branches. Like all amphibians, they have permeable skin through which water and gases, such as oxygen and carbon dioxide, can enter and leave the body. Salamanders also have glands in their skin that secrete a thick layer of mucus. On land, this mucus prevents the skin from drying out, and in water it helps maintain the correct balance of salt and water in the animals’ body fluids. Salamanders with poison-producing skin glands are often brightly coloured with distinct markings, possibly to warn predators.

Salamanders mainly feed on soft-bodied invertebrates such as insects, slugs and worms.

Images © A Monro
From top: Bolitoglossa species 2, Nototriton (dwarf salamander) genus, Bolitoglossa species 1

Morning in the canyon

On a morning walk down the slopes of the majestic Blyde Canyon, in South Africa, the Earth-Touch crew encounters several nocturnal creatures.

Watch the clip Creatures of the night to see a grey-backed tree frog, the communal nest of a social spider, and a pair of African wood owl in a quinine tree. All will be waiting out the day before resuming their nightly feeding and other activities.

Image © Earth-Touch 2008

Toad chorus

Each species of frog or toad has a unique call. You can hear a chorus of olive toads in the Earth-Touch clip, Toad song in the canyon, filmed in the Blyde Canyon in South Africa.

Their wet, textured skin has an almost metallic gleam in the dark as their throat pouches inflate to produce their croaking calls.

Image © Earth-Touch 2008

River dolphin count completed

BBC Wildlife magazine reports that the recent completion of a survey of pink (Inia geoffrensis and Inia boliviensis) and grey (Sotalia fluviatilis) river dolphins in South America’s Orinoco and Amazon Basins was “a triumph for freshwater dolphin conservation”.

The study counted more than 3000 dolphins and covered the species’ greatest threats, habitat and potential conservation strategies.

The communications director for World Wildlife Fund Colombia, Julio Mario Fernández, said one early conclusion scientists could draw was that river dolphins in the Amazon were doing better than those in the Orinoco, which flows through Colombia and Venezuela before emptying into the Atlantic Ocean. “This is the first phase of a wider programme to preserve freshwater cetaceans in these areas,” he added.

The pink Amazon River dolphin (also known as the boto) faces extinction in some tributaries due to industrialisation and the resultant destruction of the South American rainforest. Commercial fishing and poisoning are other threats facing river dolphins. However, they are rarely hunted by locals.

A unique characteristic of the pink river dolphin is the unfused vertebrae in its neck, which allows its head to turn 180 degrees. Another is the stiff hairs on the beak, which allow it to sense prey in muddy rivers. These dolphins have a hump on their backs instead of a dorsal fin.

Grey dolphins (known as tucuxi) are more numerous and are found in fresh and salt water. They, too, were not threatened by traditional communities of South America.

Across the globe in Asia, the Gangetic dolphin (Platanista gangetica) is hunted by fishermen in eastern India as a bait preparation. However, the Hindu News Update Service reports that an alternative bait developed from the internal organs of commercial fish species may help to save the lives of these rare mammals.

Image of pink river dolphin courtesy: Wikipedia

Weavers at work

The spectacled weaver is an impressive nest-builder, as you can see in the Earth-Touch clip, Weavers work on a nest.

First, the birds strip the leaves off the stem on which they are going to attach the nest, unless the tree is a fir or palm. They then tightly weave strips of fine plant material into a structure which has a downward-pointing entrance tunnel.

Sometimes, several nests are built close together, though the male is monogamous.

Eggs are laid in the months September to February and are incubated for two weeks.

The male spectacled weaver has a black chin; the female’s chin is yellow.

Image © Earth-Touch 2008

More to giraffes than meets the eye

The journal BMC Biology has published research suggesting that African giraffe populations usually recognised as subspecies of Giraffa camelopardalis may potentially represent different species.

The authors say there is clear geographic variation in traits such as coat pattern and that there are no extrinsic reasons why genes could not be exchanged between these groups. Giraffes are widespread and mobile.

On the basis of DNA analysis, they say there are at least six lineages of giraffe in Africa, which do not seem to have interbred. There are also distinct genetic groups within five of the lineages.

The results have implications for giraffe conservation, they say.

BBC News reports the lead researcher, geneticist David Brown of the University of California Los Angeles, as saying: “Lumping all giraffes into one species obscures the reality that some kinds of giraffe are on the brink. Some of these populations number only a few hundred individuals and need immediate protection.”

Image © Earth-Touch 2008

Pretenders to the bee throne

The Cape honey bee (Apis mellifera capensis) is the only bee species whose workers can produce females from unfertilised eggs. This allows them to compete with the colony’s queen in producing the next queen. A queen bee develops from an ordinary larva if it gets special food.

University of Sydney researcher Lyndon Jordan carried out a genetic study of South African bees showing that 23 out of 39 new queens were the offspring of workers, not old queens. What is more, most of the eggs were laid by workers from other colonies, not resident workers.

The intruder workers get into the colony by wearing a “queen perfume” which disguises them, says Jordan in an ABC report.

His research is published in the Proceedings of the Royal Society B journal.

See a swarm of honey bees in the Earth-Touch clip, Bees break away, filmed in the Blyde Canyon in South Africa.

Image © Earth-Touch 2008

The marula tree

This tree, Sclerocarya birrea, is found in Botswana, Zimbabwe, South Africa, Namibia and Swaziland, amongst other African countries. It bears small, round fruit, yellow when ripe and green when unripe, which can be harvested from January to March.

There are countless myths and legends about this tree.

It is a fact, however, that marula wood is traditionally used for carving pestles and mortars and for making floors, boxes, tool handles, canoes, furniture, tools, yokes, plates, bowls, beehives, toys, ornaments and drums.

The Northern Sotho people of South Africa have a myth that the marula tree was given to the people by the spirits and is sacred. Often during the First Fruits ceremony, a goat or black bull is slaughtered at a selected marula tree, where marula beer in a clay pot is offered to the ancestors.

To the Zulu people it’s also known as the marriage tree because it is a symbol of fertility and used in cleansing rituals before marriage.

The bark of the tree has medicinal properties. It can be used in the treatment of dysentery and diarrhoea and as a malaria prophylactic. It also contains antihistamines and is used for cleansing when the bark is steeped in boiling water and the steam inhaled.

Amongst the Venda a woman who wants a baby boy may take a mixture made from the bark of the male tree, or if she hopes for a girl, from the female tree. If the child born is not of the desired sex, then it is said to be very special in being able to disregard the spirits. Another traditional practice is that newborn girls and their mothers are washed in water heated on a fire of marula twigs so that the baby may be fertile.

In Swaziland, as the women pick up marula fruit from the ground to prepare for the Xikuha Marula Festival, they look for worms in the fruit. Worms signify that the planting season is ready to start. As they move from home to home in celebration of the marula, they believe that it chases away the worms from the fields. Some scientific evidence does back this myth – as the fruit on the ground ripens, worms are attracted to the sugar in the fruit, and this alerts the women to the risk of worms for their crops. They then spread the marula fruit around the area and the worms do disappear.

The leaves of the marula are used as dressings for burns and wounds, as a relish in food and to relieve heartburn.

The fruit is eaten whole by people and a variety of animals. It is juicy and aromatic and the size of a small plum. It may be eaten fresh and the flesh has a high vitamin C content. It may also be cooked to produce jam and juices.

The kernels, rich in oil and protein, are ground up to make porridge, condiments and cereals and the oil is used as a skin cosmetic.

An alcoholic beverage called mampoer is produced from overripe marula fruit.

There are rumours that the fruit intoxicates animals. Elephants and baboons enjoy the fruit, but for the elephant to get drunk it would need to eat unusual amounts of already fermenting fruit, and since these huge animals drink up to 160 litres (338 pints) of water a day, it will dilute the marula.

Go to the following Earth-Touch clips for more on the marula tree:

Pathway to another marula,

A young elephant is put in its place,

and Marula magic captivates elephants.

Image © Earth-Touch 2008

Fishy facts

The world’s smallest fish is the Paedocypris progenetica, which belongs to the carp family. It is the smallest vertebrate, being 7.9mm (0.3in) long. The species was discovered in the acidic waters of forest swamps in Sumatra, Indonesia.

The largest fish is the whale shark (Rhincodon typus), most specimens being in the length range of 5-8m (16-26ft). A specimen of 20m (66ft) long has been reported. They are about 60cm (24in) long at birth and a female produces about 300 pups at once. (See the Earth-Touch clip, Encounter with a big fish.)

A person who studies fish is called an ichthyologist.

Fish secrete mucus from their skin, a coating which gives them protection against parasites and diseases, covers wounds to prevent infections and allows faster movement in the water. This mucus is toxic for some predators. Other fish use this mucus to feed their young.

Images of Paedocypris progenetica: Maurice Kottelat, Raffles Museum of Biodiversity Research, National University of Singapore

Coatis in a palm grove

The coati (Nasua nasua) is a raccoon-like mammal with a ringed tail and a long, flexible nose which is somewhat turned up, allowing it to nose about under leaf litter for food. Watch a group of coatis doing this in the Earth-Touch clip, Coatis forage in a palm grove, filmed in the Pantanal of Brazil. These forest dwellers eat fruit and invertebrates.

Females and young males live in groups, but older males are usually solitary, like the one in the clip, On the coati trail.

Coatis’ forelimbs are adapted for climbing and digging for food. They can come down from trees head first because of reversible joints in the anklebone.

Image Earth-Touch 2008

Did You Know? Coyotes

The coyotes (Canis latrans) found in Yellowstone National Park are among the largest in the United States; adults average about 14kg (30lb). They are slighter in build than their relative, the grey wolf (Canis lupus), but can kill large prey, especially when hunting co-operatively. Such attacks can go on for hours.

They hunt small mammals alone, however, as seen in the Earth-Touch clip, Coyote hunts in Yellowstone.

Coyotes are found in most habitats, including urban areas, and can eat a wide range of food, including insects and fruit.

When wolves were returned to Yellowstone in 1995, it was expected that the two canid species would compete. Coyote numbers have declined but they are still common in the park and apparently the packs have become more cohesive.

Packs have a hierarchical structure and are spaced in a landscape according to the availability of food. Information like territorial boundaries and the presence of alpha animals is communicated with howls.

Image © Earth-Touch 2008

The week’s most viewed stories

The most popular stories on Earth-Touch in the past week (from Friday 04 January to Thursday 10 January 2008) were:

Number 1

Crowd of Zambezi sharks

These predators patrol the waters constantly, looming powerfully into view with a steely sheen.

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Number 2

Baboons in leadwood tree

Alert males keep watch, while others play and rest in the treetops.

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Number 3

A predator’s paradise

The sheer volume of fish at Bass City of the coast of southern Mozambique makes it an ideal hunting ground for hungry predators.

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All images © Earth-Touch 2008

Did you know? Blue wildebeest

This gregarious grazer is found in abundance in the grasslands and floodplains of the Okavango Delta, Botswana.

Wildebeest (Connochaetes taurinus) are territorial animals, creating ‘rolling grounds’ where they deposit their faeces. They also rub their horns on trees to stake out their territory.

These diurnal herbivores are highly social, therefore the spreading of their scent is clearly a means of communication. The idea of safety in numbers is also a reason for their herd behaviour.

Wildebeest are a favourite meal of lions and other carnivores.

See these animals in the Earth-Touch clips Wildebeest at sunrise and Unease at the waterhole.

Image © Earth-Touch 2008

Sharks at the Pinnacle

At this time of the year a dive into the Indian Ocean at the Pinnacle reef off Ponta Malongane in southern Mozambique will often be rewarded with sightings of game fish and sharks.

In the Earth-Touch clip, Zambezi sharks act shy, large shoals of pelagic fish, among them kingfish and seapike, are seen around the Pinnacle. Predators like Zambezi sharks and blacktip sharks follow them.

The Zambezi sharks in this footage preferred to remain deeper than the divers.

However, the camera was met by numerous blacktip sharks at close range. They are the more outgoing of the sharks.

Image of blacktip shark © Earth-Touch 2008

What an elephant nose

Elephants can recognise their relatives from the smell of their urine, according to research published in the journal Biology Letters.

Scientists led by Professor Richard Byrne of the University of St Andrews in Scotland designed experiments in Kenya to test whether elephants could distinguish kin from strangers and whether they could keep track of where other elephants were in the group.

Prof Byrne, professor of evolutionary psychology, has also been involved in research that found elephants could recognise and distinguish between humans who had posed a threat to them in the past and those who had not.

Watch a large herd of elephants on the move in the Okavango Delta, Botswana, in the Earth-Touch clips Elephant families cross flood plain and Bush thick with elephants.

Image © Earth-Touch 2008

Did you know? Sweepers

Small fish known as sweepers are found in the Indian Ocean waters of southern Mozambique.

These fish have flattened bodies, large eyes and a single dorsal fin and are often found at reefs, shipwrecks and caves.

In the Earth-Touch clip, Shimmering shoal, golden and red slender sweepers (Parapriacanthus ransonneti) are seen swimming in a dense shoal. This species forms shoals during the day and scatters at night to feed on plankton. Sweepers are generally nocturnal fish.

The slender sweeper grows to just 7.5cm (3in), compared with the 17cm (7in) attained by the more common dusky sweeper (Pempheris adusta).

Image © Earth-Touch 2008