DNA extracted from 40,000 year old giant kangaroos


This video is called When did Marsupial and Placental Mammals split?

From Wildlife Extra:

Scientists extract DNA from 40,000 year old giant kangaroos

The study of DNA reveals that the red kangaroo was a close relative of the extinct giant wallaby

A team of scientists led by Dr Bastien Llamas and Professor Alan Cooper from the University of Adelaide‘s Australian Centre for Ancient DNA (ACAD) have succeeded in extracting DNA sequences from two extinct Australian species: a giant short-faced kangaroo (Simosthenurus occidentalis) and a giant wallaby (Protemnodon anak).

These specimens died around 45,000 years ago and their remains were discovered in a cold and dry cave in Tasmania.

Relatively good preservation conditions in the cave allowed enough short pieces of DNA to survive so researchers could reconstruct partial “mitochondrial genomes” ─ genetic material transmitted from mother to offspring and widely used to infer evolutionary relationships.

“The ancient DNA reveals that extinct giant wallabies are very close relatives of large living kangaroos, such as the red and western grey kangaroos,” says lead author Dr Bastien Llamas, ACAD senior research associate.

“Their skeletons had suggested they were quite primitive macropods, a group that includes kangaroos, wallabies, pademelons and quokkas, but now we can place giant wallaby much higher up the kangaroo family tree.”

The research has also confirmed that short-faced kangaroos are a highly distinct lineage of macropods, which had been predicted on their unusual anatomy.

Although the ancient DNA confirms that the short-faced kangaroos left no descendants, it also shows their closest living cousin could be the banded hare-wallaby (Lagostrophus fasciatus), which is now restricted to small isolated islands off the coast of Western Australia.

“Our results suggest the banded hare-wallaby is the last living representative of a previously diverse lineage of kangaroos,” says co-author Professor Mike Lee of the South Australian Museum and the University’s School of Biological Sciences.

“It will hopefully further encourage and justify conservation efforts for this endangered species.”

Rare spectacled hare-wallaby seen in Western Australia


This video from Australia is about the rufous hare-wallaby. They are relatives of the recenttly rediscovered spectacled hare-wallaby.

From Wildlife Extra:

Rare Spectacled Hare-wallaby sighted in Western Australia

The threatened Spectacled Hare-wallaby has been sighted near Broome in Australia after nearly a decade without any recorded sightings in Kimberley region.

Although the species is widespread throughout other parts of northern Australia, the wallaby, which gets its name from its distinctive orange fur that surrounds each eye, is considered very rare in the Kimberley region and numbers here are declining.

“We need to keep a close eye on the threats to this rare and fascinating animal so we get the right information to help it survive into the future,” said Dr Alexander Watson of WWF-Australia.

“Their shelter and feeding requirements make them highly sensitive to habitat changes, so assessing their numbers is a good indicator of overall health of the local environment.”

The Spectacled hare-wallaby uses large grass tussocks for shelter from predators and the extremely hot daytime temperatures. Inappropriate fire regimes and trampling by larger animals can put the wallaby at risk of exposure.

The Spectacled hare-wallaby is well suited for life in extreme arid conditions, having adapted to extract and retain water from their food. However, their population is still at risk from modern threats such as introduced predators, grazing, frequent fires and extreme weather events like droughts.

Koalas told apart by their noses


This video from Asustralia says about itself:

A heart breaking story – In the eucalypt forests of east coast Australia lives one the world’s most loved animals, the koala. Join Jenny Brockie as she observes a year in the life of Arnie (King Koala) and his group of females and offspring. Arnie, Lulu and Marie must fight off threats from rival males, goannas, snakes and feral dogs in order to maintain the group and Arnie’s ascendancy.

From Wildlife Extra:

Individual Koalas can be told apart by their noses

Individual Koala Bears can be identified by their nose says new research, as each Koala has a unique ‘noseprint’, just like a human fingerprint.

Janine Duffy from the wildlife tour operator Echidna Walkabout, which carried out the research, said: “A few years ago I was looking up at one Koala thinking, ‘Gee, I wish I could tell you guys apart’ and I just looked at the nose through my binoculars and I thought ‘Oh my God! They’re all different.’ I knew this could be important because I’d found a way of learning about Koalas without having to touch them.

“Up until then, Koalas could only be monitored by catching them and releasing them with a GPS collar. They are animals that get stressed easily, and wild ones like to keep their distance from humans. Catching and dragging them out of a tree to do research can be very harsh.”

After the initial discovery, Janine and her team have recorded the nose patterns of 108 wild koalas over 16 years, and identified that not one has changed substantially in that time.

Their research has led to important discoveries about Koala behaviour, and Janine believes it could play a major step in helping the species survive.

“I’d love to see a national online koala database, with tourists and locals contributing photographs to help identify Koalas and track their movements and behaviour,” she said. “It’s part of my grand dream that every Koala in Australia would be known.”

Extinct giant kangaroos, new research


This music video is called Saint Saens: Carnival of the Animals~Kangourous (Kangaroos).

From daily The Independent in Britain:

The mystery of the extinct giant kangaroo is solved – it didn’t hop

The giant Sthenurus – dead for 30,000 years – was three times the size of the modern-day kangaroo

Steve Connor, science editor

Wednesday 15 October 2014

It looked like something out of the pages of Alice in Wonderland but this giant, short-faced kangaroo hid another peculiar characteristic down its pouch – it walked rather than hopped on its hind legs.

The extinct marsupial, which was nearly three times bigger than the largest living kangaroos, died out 30,000 years ago, but only now have scientists been able to tie its locomotion down.

With a leap of the imagination, the researchers were able to visualise how the giant Sthenurus kangaroo, which weighed up to 240kg, moved around by putting one foot in front of another rather than hopping on both legs.

Bipedal hopping is a quintessential feature of kangaroo locomotion, but the Sthenurine group of extinct ‘roos was clearly made for walking, according to Christine Janis of Brown University in Providence, Rhode Island, who led the study published in the on-line journal PlosOne.

“When I first saw a mounted skeleton of a Sthenurine I was struck by how different it was in the back end to modern kangaroos, despite the superficial similarity of long hind legs,” Dr Janis said.

“My work emphasises that the large modern kangaroos are highly specialized in their anatomy for hopping in comparison with other large extinct kangaroos,” she said.

“Sthenurines almost certainly did hop, except perhaps for the very largest ones. The issue is that their anatomy is also suggestive of bipedal walking, which is the unexpected issue here,” she added.

Modern kangaroos use hopping to move around at speed but when moving slowly they walk mostly on all fours, using their massive tails as support – so-called “pentapedal” locomotion.

The extinct Sthenurus, however, must have walked on its hind legs because its anatomy does not fit with the notion of hopping or pentapedal locomotion, Dr Janis said. For a start, it had “robust”, heavier bones compared with the more slender anatomy of modern kangaroos, which would have made hopping hazardous.

“If it is not possible in terms of biomechanics to hop at very slow speeds, particularly if you are a big animal, and you cannot easily do pentapedal locomotion, then what do you have left? You’ve got to move somehow,” Dr Janis said.

An analysis of the giant kangaroo’s anatomy suggests it was well suited to bearing the animal’s entire weight on one leg, which is crucial for bipedal walking. Its ankle bone, for instance, had a flange over the back joint to provide extra support – something missing in modern kangaroos.

Sthenurus has proportionately bigger hip and knee joints than today’s kangaroos and the shape of its pelvis – broad and flared – suggested that it had large gluteal muscles in is backside, which would have allowed it to balance on one leg as it moved the other leg forward, Dr Janis said.

“I think that they originally took this up as an alternative slow gait to the way that other kangaroos move slowly on all fours using their tail to propel their hind legs past their front legs [because] hopping is biomechanically impossible at very slow speeds,” Dr Janis said.

“This requires a flexible back and supporting their weight on their hands, whereas sthenurines had a stiff back and specialized hands for feeding. So they had this unique walking gait,” she said.

Sthenurine kangaroos died out around the same time that modern humans arrived in Australia and began to spread across the continent, suggesting that their demise may have had something to do with human hunting.

Walking rather than hopping would have been a slower and less efficient means of moving fast, which may have been one of the reasons by the giant, walking kangaroo went extinct, leaving their hopping cousins to fill the void, Dr Janis explained.

Venezuelan opossums and the origin of species


This video, in Spanish, from Venezuela about a mouse opossum is called Marmosa robinsoni.

From Wildlife Extra:

New study could change the traditional view of how species come about

A team of researchers from the City University of New York working on the Península de Paraguaná in Venezuela have made a discovery that could revolutionise our understanding of how the origin of a new species takes place.

Up to now it has been accepted that the primary drivers in a species becoming isolated, and consequently developing sufficiently separate characteristics to become genetically distinct, are physical in nature – the uplift of mountains, the formation of islands, the change in the course of a river, creating barriers.

The findings of the study of two species of mouse opossums, Marmosa xerophila and Marmosa robinsoni, have now added interactions among species as another way that populations can become geographically isolated, which could promote the formation of new species.

In their paper the authors, Eliécer E Gutiérrez, Robert A Boria and Robert P Anderson, say that these interactions might include, ‘the presence of particularly effective predators or strong competitors, or the absence of important prey or essential mutualistic species.’

This new theory has come about as a result of observations on the Paraguaná peninsula, which is separated from the mainland only by a spit of sand, in which the researchers found that M. robinsoni has become separated from populations of the same species found on the mainland, not because the habitat in between is unsuitable, but because it is mostly occupied by M. xerophila.

The inability of individuals of that population of M. robinsoni to mate with individuals of mainland populations could, in time, lead to their genetic differentiation and the origin of a new species.

To read more about the study go to www.ecography.org/content/august-2014.

Kangaroos need their tails, new research


This video is called Kangaroo Walking.

From Wildlife Extra:

A fifth leg helps kangaroos walk

Red kangaroos may be one of nature’s best hoppers, able to lope along at speeds of up to 12 miles an hour on their hind legs, while their two front legs seem to dangle obsolete.

But when they are grazing or walking, which is actually most of the time, not only do they need those front legs but also their tail, which a new study has dubbed their fifth limb.

“We found that when a kangaroo is walking, it uses its tail just like a leg,” said study author Associate Professor Maxwell Donelan of Simon Fraser University in Canada.

“They use it to support, propel and power their motion. In fact, they perform as much mechanical work with their tails as we do with one of our legs.”

When grazing on grass red kangaroos, which are the largest of the kangaroo species in Australia, move both hind feet forward “paired limb” style, while working their tails and front limbs together to support and move their bodies.

“They appear to be awkward and ungainly walkers when one watches them moseying around in their mobs looking for something to eat,” said co-author Associate Professor Rodger Kram.

“But it turns out it is not really that awkward, just weird. We went into this thinking the tail was primarily used like a strut, a balancing pole, or a one-legged milking stool.

“What we didn’t expect to find was how much power the tails of the kangaroos were producing.

“It was pretty darn surprising.”

However when the roos are in their faster, hopping gait the tail returns to being a dynamic, springy counterbalance.

Echidna hatching from egg, video


This video says about itself:

The echidna is quite unique as it’s a mammal that lays eggs rather than giving birth to live young. This clip is an excerpt from our 1974 production, “Comparative biology of lactation”. A young echidna is called a puggle.

Video transcript available here.

From Smithsonian magazine in the USA:

Watch This Adorable Mammal Hatch From an Egg

A 1974 nature video shows a spiny anteater hatching

By Mary Beth Griggs

Via one of our favorite video blogs, The Kids Should See This, check out this incredible video of an echidna—also known as a spiny anteater—hatching from an egg. Echidnas live in Australia and on the island of New Guinea, and they are some of the only egg laying mammals in existence, along with the fantastically weird platypus.

Australia’s Commonwealth Scientific and Industrial Research Organization, or CSIRO, made this video in 1974. On the organization’s YouTube page, there are many more examples of wonderfully weird old example[s] of animal videos, including vintage favorites like the echidna hatching or a 1965 educational video about the birth of a red kangaroo. (That last one shows the actual birth of a live kangaroo and is not for the faint of heart.)

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