Australian quokkas and plants, new study


This video from Australia is called Quokka with baby.

By Shannon Verhagen in Australia:

April 9, 2015

Mapping the future of Rottnest‘s furry friends

We all know Rottnest Island‘s iconic quokkas (Setonix brachyurus) love eating treats from tourists and poking around inside public buildings but local researchers have identified plant species on the island that the quokkas need for food and shelter.

The Murdoch University study identified eight plant species used for food and four used for shelter by the quokkas and mapped their extent and distribution using hyperspectral remote sensing data.

They collected fresh faecal samples from 210 quadrats across the islands’ twelve native vegetation types over a two week period in 2011 to conduct dietary analysis.

The study found a clear preference for Guichenotia ledifolia, a non-significant food source for Rottnest Island quokkas 50 years ago, which suggests compositional changes in island vegetation over time may have caused this species to be more dominant in the landscape.

Researcher Patricia Fleming says a history of grazing, fire and land clearing has altered Rottnest’s vegetation structure and composition and therefore the quokkas’ vegetation use.

“The diet of these animals is likely to have changed over the last 50 years and probably has shifted from that of over 200 years ago,” Ms Fleming says.

“The vegetation on the island has changed markedly over that time, largely due to anthropogenic influences.”

Quokkas were found to have a clear preference for Melaleuca lanceolata and Acacia rostellifera for shelter, highlighting the importance of dense, protective vegetation.

They used remotely sensed, hyperspectral airborne imagery to map the principal food and shelter species in order to determine the locations where the preferred species are evident and where the principal species overlap.

Ms Fleming says managing these key habitat locations is essential as the Rottnest Island population suffers severe seasonal crashes due to a lack of permanent water bodies and intense browsing pressure from other quokkas.

“There are definitely times of the year for example, at the end of summer when the first cold nights hit those that are in worst condition, that animals are likely to be physiologically stressed,” Ms Fleming says.

“The forest [on the mainland] has more resources and the animals can probably access a much greater area to obtain their requirements.”

“The Rottnest Island population is resource limited.”

“It is likely that loss of a key plant species will alter the carrying capacity of the island,” she says.

More information: “Spatial analysis of limiting resources on an island: diet and shelter use reveal sites of conservation importance for the Rottnest Island quokka.” Wildlife Research, 41(6), 510.

Snakebite antivenom discovery in American opossums


This video from the USA says about itself:

Virginia Opossum Family

12 July 2012

A short video clip of a Virginia Opossum family in wildlife rehabilitation at Evelyn’s Wildlife Refuge, Virginia Beach, VA. The mother Opossum came into care with an eye injury and front feet injuries.

From the East County Magazine in the USA:

SNAKEBITE ANTIVENOM SOURCE FOUND IN OPOSSUMS

By Miriam Raftery

April 5, 2015 (San Diego’s East County) – Opossums aren’t typically thought of as a powerhouse in the animal kingdom. The term “playing possum” after all refers to one way opossums react to predators –by playing dead. But it turns out that opossums have a peptide that gives them a natural immunity to snakebites and other toxins – and now scientists are working to harness it to create anti-venoms.

Scientists have isolated the peptide, and in lab tests with mice exposed to venom, those opossum peptides proved effective against Western diamondback rattlers and Russell’s vipers from Pakistan. The results offer hope that a universal antivenom could be developed to counter the poisonous effects of snakebites from multiple species, National Geographic reports.

That’s big news, since worldwide, about 421,000 poisonous snake bites occur each year, and 20,000 deaths result, according to International Society on Toxicology. Human testing is next on the horizon.

Moreover, Newswise reporters, scientists found they could reproduce the peptide from E-coli bacteria, meaning it can be replicated cheaply and easily—no opossums need to be harmed in the process. Unlike standard snakebite anti-venoms, this one has thus far produced no serious side effects such as wheezing, rash or rapid heartbeat.

The anti-venom may even prove effective against other forms of toxins, since opossums also have a natural resistance to poisonous scorpions and some forms of toxic plants as well.

The results were presented in late March at the National Meeting and Exposition of the American Chemical Society in Denver.

The opossum, which resembles a large rat, is a marsupial tracing its origins back 65 million years, around the time dinosaurs went extinct. But only now have we learned a key secret to its survival against threats that kill many other animals.

So the next time you see a lowly opossum hanging by its tail from a fence or waddling across a road, remember – this ancient animal just may hold the key to saving your life if you’re ever bitten by a snake.

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.