wildlife – Page 10 – ANGFA Queensland

Adventures of a Qld croc squad ranger

Jul 202013

Original story by Cleo Fraser, the Telegraph

"WE need to be quiet, not make any sudden movements and keep our arms inside the boat," ranger Dan Mead whispers.

It's close to midnight, it's pitch black and we're out searching for crocs in far north Queensland.

Dan, who's suddenly become very serious, has seen two small red dots peering through the dense mangroves - he's spotted the eyes of our first croc.

Over the past 28 years, seven people have been killed by crocs and there have been 19 attacks in Queensland. Picture: Marc McCormack, News Limited

We've been cruising the Hull River near the tourist town of Mission Beach for almost an hour and a half. Our mission: to record how many crocs we see.

Dan slows the motor as we move in on the croc.

"It's a 10 footer I think," Dan whispers before the croc makes a getaway, swimming under the water and out of sight.

Under Queensland's crocodile management scheme rangers keep track of croc populations. They're also tasked with trapping and removing problem reptiles which lurk near populated areas.

After a croc is reported to them by a member of the public, rangers head out to observe whether it is showing signs of aggression.

"We try and collect all the facts because when it comes to crocodile stories they can get exaggerated or people might hear about them third hand," Dan said.

"We need to determine whether that croc was actually trying to approach people or trying to retreat to a deep section of river and had to swim past them to do so."

If it's determined to be a risk then a trap - a floating metal cage fitted with a rotting piece of meat - is set.

Once the crocs are caught they're towed behind a boat and transported to a holding pen on a trailer.

"That involves holding down the animal with a team of people so we can check the animal and determine whether it's male or female," Dan said.

"We leave it in the holding pen until we've found a new home for it."

Since about June last year up to 20 crocs have been caught in the state's north, of which all have been relocated to croc farms or zoos.

Environment Minister Andrew Powell recently announced the scheme would be extended to include reducing croc numbers around populated areas like Cairns.

Environmentalist Bob Irwin has raised concerns that the crocs are killed for meat or skins and made into handbags once taken to the farms.

Mr Powell's office has not said if any of the animals ultimately end up being used for fashion accessories or meat.

The normal range for crocodiles in Queensland is considered to be from Cape York Peninsula to Gladstone, although two crocs have recently been spotted in the Mary River in Maryborough.

A three to four metre salty was recently trapped near Port Douglas, north of Cairns, after being spotted cruising the popular beach.

Department of Environment and Heritage Protection wildlife operations manager Mike Joyce says croc numbers have stayed relatively the same over recent years.

"We can basically set our watch to how many problem crocs are going to get called in," he told AAP.

He says the department takes reports of aggressive crocs seriously as rangers can be called to appear before coronial hearings if someone is killed.

Over the past 28 years, seven people have been killed by crocs and there have been 19 attacks in Queensland.

The 22 rangers in the north not only look out for crocs they also help injured animals such as cassowaries and flying foxes and educate locals.

During our two-hour croc spotting adventure along Hull River, we see just three salties - two about three metres long and a smaller one about one metre.

Dan says there's usually a lot more - spotting up to 10 in one night is normal - but at high tide the reptiles are able to hide underwater or behind mangroves.

Before taking up the role of head ranger at Innisfail, south of Cairns, five years ago Dan worked with the late croc hunter Steve Irwin at Australia Zoo.

It's fair to say he loves working with crocs.

But should those who aren't used to tackling crocs be afraid of the deadly reptiles?

"We don't necessarily want people to be fearful, we just want them to be aware of what they're doing and what environment they're in," he says.

"You just need to follow some simple rules like keeping three or four metres away from the water's edge."

Swan River ‘worse than it looks’

fisheries, waterways/wetlands, wildlife

Jul 192013

Original story by Daniel Mercer, The West Australian

The Swan River is like a cemetery, according to world-renowned WA water expert Jorg Imberger.

The University of WA professor makes the comparison to illustrate that not everything is as it seems.

At face value it appears peaceful, picturesque even, but look below the surface and there is death and decay.

Dying trees on the Swan River near Garratt Road Bridge. Picture: Mogens Johansen, The West Australian

"If you look at the surface, the river still looks quite good," Professor Imberger said. "It's unfortunate because it's a veneer."

For more than 25 years, Professor Imberger and his team of scientists at UWA's Centre for Water Research have been checking the pulse of the river with increasing concern.

Last week, they gave The West Australian an insight into their work as they tested the water quality from Fremantle, just before it meets the Indian Ocean, to Guildford, almost 50km upstream.

Although the results were markedly better than those taken as recently as June, they paint a picture of a river system battling for the vital signs that indicate life, let alone healthiness.

Oxygen levels, apart from the ocean-like environment at the river mouth in Fremantle, were modest or low, and salinity and chlorophyll concentrations - a key precursor to algal blooms - were elevated.

Crucially, the results also underlined an entrenched and damaging phenomenon winding an increasingly tight grip around the Swan - a process known as stratification.

Heavy seawater moves upstream, forcing fresher water flowing downstream over the top.

The heavier water, which used to be washed out to sea every year before the big decline in Perth's winter rainfall, now effectively sits at the bottom and stagnates, allowing organic material in it to break down and consume oxygen.

The upshot, Professor Imberger said, was that the lower depths of the Swan River could become deaths zones in which no life could survive.

"In any other place in the world … it would be classified as a disaster," Professor Imberger said. "The problem is it's hidden here. A few dolphins come in at the surface and people think, 'Oh, it looks great, what are you talking about?' "

The Swan River Trust concedes the river is struggling with the effects of a drying climate and urban encroachment but disputes it is dead in parts or even dying.

River systems manager Mark Cugley points to anecdotal evidence that numbers of fish, including black bream, are abundant and populations of blue manna crabs, prawns and cobblers might be recovering.

Mr Cugley said low oxygen levels of the kind recorded last week were "not ideal" but were not an immediate danger.

He touches on the trust's $40 million healthy rivers action plan to describe how the agency was focused on reducing nutrients entering the river to improve its health.

Dismissing claims of abundant fish life as "nonsense", Professor Imberger says the Swan's plight is serious and in the short term consideration should be given to a barrage under Stirling Bridge to stop intrusion of saltwater upstream.

Traps set to catch second croc seen in Qld’s Mary River

government, wildlife

Jul 192013

Original story by Alyse Edwards, ABC News

Queensland's Environment Department is trying to trap two crocodiles in the Mary River on the Fraser Coast.

Rangers have been trying to catch the 3.5 metre croc since April, but now another 2.6 metre 'saltie' has been spotted near Maryborough on Wednesday.

The big croc lazes on the banks of the Mary River near Maryborough in May 2012. Photo: Brad Marsellos, ABC Wide Bay

Environment Minister Andrew Powell says the two crocs were seen floating about 100 metres apart,

"Our elusive Mary croc has come up with a friend and one of our officers literally saw both crocodiles on either side of his boat," he said.

Mr Powell says it is unusual to see the reptiles so far south.

"Sightings south of the Boyne River are extremely rare, and the policy is if a crocodile is sighted, regardless of size, regardless of behaviour, it will be removed," he said.

"We will make every effort to do so - they're significantly south of what we consider the most southern reaches of crocodile populations."

Saltwater crocodiles

One of two species in Australia - saltwater [Crocodylus porosus] and freshwater [Crocodylus johnsoni] - but both can live in either fresh or salt water
'Croc country' typically reaches as far south as the Boyne River near Gladstone, 500km north of Brisbane
Crocs mostly live in tidal reaches of rivers but also move in lagoons, rivers, and swamps up to hundreds of kilometres inland
An average male may be 3-4m long and weigh 200-300kg. Females rarely reach over 3.5m and weigh up to 150kg.
More aggressive in breeding season, which runs from September to April

Sources: Queensland Department of Environment and Resource Management, Queensland Environmental Protection Agency [now Environment and Heritage Protection].

Mr Powell says baited traps have been set in the river to catch the two reptiles.

He says the traps have so far failed to catch the larger crocodile since it was first sighted in April last year.

"As approached by humans and boats, it is appearing very timid," he said.

Residents warned to be cautious

He says rangers will continue with trapping attempts but locals should be cautious near the river.

"In the meantime, I do encourage all residents in that area to be very croc-wise - to stay away from the water, to keep their domestic pets away from the water," he said.

"If casting nests, to step back from the water and if they do see any sightings, let us know.

"In this instance it's a fairly smaller crocodile, but it does demonstrate that there could be more there and people need to be very aware and alert."

Indigenous land managers to help with turtles, dugongs conservation

community, government, wildlife

Jul 182013

Original story by Allyson Horn, ABC Indigenous

The Federal Government has given $1 million towards the conservation of sea turtles and dugongs in northern Queensland.

Mother and baby dugong carved from rain tree timber by Dennis Nona, on display in Bipotaim. Photo: National Museum of Australia.

The money will be split between eight groups in the region for them to maintain marine environments and raise community awareness about the species.

Federal Environment Minister Mark Butler says the Indigenous land managers are some of the best people to carry out the work.

Mr Butler says it is important to use the generations of local knowledge.

"They've been living in this part of Queensland for literally thousands and thousands of years," he said.

"They understand the topography and the habits of dugongs, sea turtles, other endangered species in this area that they have been sustainably harvesting for literally hundreds of generations.

"Building on that understanding, so that all of us in this part of Queensland and Australia can understand a sustainable way in which to live along the reef is going to be for the betterment of us all."

Stanford researchers reveal great white sharks’ fuel for oceanic voyages: liver oil

research, wildlife

Jul 182013

Original story by Rob Jordan, Stanford News Service

A juvenile great white shark (Carcharodon carcharias) at the Monterey Bay Aquarium. Photo: Randy Wilder

New research shows that great white sharks power their non-stop journeys of more than 2,500 miles with energy stored as fat and oil in their massive livers. The findings provide novel insights into the biology of these ocean predators.

Great white sharks are not exactly known as picky eaters, so it might seem obvious that these voracious predators would dine often and well on their migrations across the Pacific Ocean. But not so, according to new research by scientists at Stanford University and the Monterey Bay Aquarium.

The researchers' findings, published July 17 in Proceedings of the Royal Society B, reveal previously unknown details of how great white sharks power themselves and stay buoyant on non-stop trips of more than 2,500 miles. The discoveries have potentially broad implications for conservation and management of coastal waters.

"We have a glimpse now of how white sharks come in from nutrient-poor areas offshore, feed where elephant seal populations are expanding – much like going to an Outback Steakhouse – and store the energy in their livers so they can move offshore again," said researcher Barbara Block, a professor of marine sciences and a senior fellow at the Stanford Woods Institute for the Environment. "It helps us understand how important their near-shore habitats are as fueling stations for their entire life history."

Just as bears put on fat to keep them going through long months of hibernation, ocean-going mammals such as whales and sea lions build up blubber to burn on their long migrations. Until now, little was known about how sharks, which carry fat in their massive livers rather than external blubber, make similar voyages.

In a study initiated by a summer project of Stanford undergraduate student Gen Del Raye, researchers first looked at a well-fed juvenile great white shark at the Monterey Bay Aquarium. They documented over time a steady increase in buoyancy as the shark's body mass increased, presumably due to the addition of stored oils in its liver.

The researchers then turned to detailed data records from electronically tagged white sharks free-swimming in the eastern Pacific Ocean. Using these data, which include location, depth and water temperature, the scientists identified periods of "drift diving," a common behavior of marine animals in which they passively descend while momentum carries them forward like underwater hang gliders.

By measuring the rate at which sharks sink during drift dives, the researchers were able to estimate the amount of oil in the animals' livers, which accounts for up to a quarter of their body weight. A quicker descent meant less oil was present to provide buoyancy. A slower descent equated with more oil.

"Sharks face an interesting dilemma," said Sal Jorgensen, a research scientist at the Monterey Bay Aquarium. "They carry a huge store of energy in the form of oil in their massive livers, but they also depend on that volume of oil for buoyancy. So, if they draw on those reserves, they become heavier and heavier."

Buoyancy consistently decreased over the course of each studied shark's migration, indicating a gradual but steady depletion of oil in the liver. In other words, they were primarily running on energy stored up before they embarked on their journeys.

"The most difficult thing about this research was finding a way to bring all of the different sources of data together into a coherent and robust story," said Del Raye.

Part of that story is the importance of calorie-stocked coastal feeding grounds, not just for mammals such as whales, but also for sharks readying for long-distance migrations. Could the same be true for other ocean animals such as sea turtles and a variety of fish? The study may help answer that question too through a novel technological approach that can be applied to ongoing studies of other large marine animals.

Whaling in the Antarctic: the case concludes

wildlife

Jul 182013

Original story by Tony Press, University of Tasmania at The Conversation

Australia and Japan’s case on whaling in the Antarctic, heard in the International Court of Justice, wound up on Tuesday. In presenting Japan’s final arguments Professor Payam Akhavan of Harvard University claimed “it would not be an exaggeration to say that Australia’s case now hangs by a thread”.

And now we wait… the International Court of Justice has heard final arguments in Japan and Australia’s whaling case. Photo: International Court of Justice

Utilisation, not preservation

Japan said that the Court should look at “the applicable law” of the Whaling Convention and again argued that its purpose was the “conservation and management of whale stocks” and the “optimum utilisation of the whale resources”. Sustainable whaling is clearly one, if not “the fundamental objective" of the Whaling Convention, Japan said. “But Australia does not accept sustainable commercial whaling”.

In response to arguments from Australia and New Zealand regarding Special Permit Whaling under the oft mentioned Article VIII of the Convention, Japan said that it was “an exemption from the Convention, an exemption that permits whaling for the purposes of scientific research”. This exemption, Japan argued, allowed each State freedom to decide for itself what should be included in its program of scientific research.

An ANZAC collusion

Referring to a 2010 joint press release from the then Australian Foreign Minister, Kevin Rudd, and New Zealand’s Foreign Minister Murray McCully, Japan said the two Parties “have acted in collusion in this case” and “clearly prejudiced Japan in these proceedings”.

Japan also referred to interviews with Australian Attorney-General Mark Dreyfus. Japan said it was clear that “irrespective of the Court’s decision, Australia will continue its campaign of confrontation at the IWC” and that “Australia will stop at nothing”.

Science on trial – but what is art?

On Australia’s arguments about science, Japan said “Australia’s best case is that there is some scientific disagreement” on aspects of Special Permit whaling. “But the question before the Court is not whether Japan could improve its scientific research. It is whether it has no scientific merit at all; or whether it is commercial whaling in disguise”.

Emeritus Professor Lowe, an expert on international law from Oxford University, argued for Japan that “there is no uniquely correct formula” for what is scientific research. He said that there might be differences among scientists about Japan’s Special Permit whaling, but “these are debates about scientific questions”. He went on to say “the Court can ask: could a reasonable State regard this [JARPA II] as a properly framed inquiry? But it can no more impose a line separating science from non-science than it could decide what is or is not Art”.

While some might think Japan’s whaling program is bad science or unnecessary science, Japan’s view is that it is “an absurd exaggeration to say that it is not scientific research at all”.

Science – implications for other international agreements

Professor Allan Boyle from the University of Edinburgh argued that if Japan’s lethal whaling program was not scientific research, “then neither are the research activities of institutions providing advice on sustainable catch levels for fisheries worldwide”. He went on to say that the case could have “broad systemic” implications across the whole field of international environmental law.

In summing up on the last day of the case, Professor Alain Pellet of the University of Paris Ouest, said Australia had “an elitist and metaphysical view of science”. He went on to say that some scientists’ “anti-whaling bias might be stronger than their objectivity”.

Bad faith and fig leaves

On Australia’s arguments about “bad faith”, Japan said that this was a “legal euphemism for intentional deception. Australia’s case is that Japan has lied, and that it has done so systematically, as a matter of State policy for almost 30 years”. Japan said that this was a serious accusation and an affront to a nation.

Japan again argued that it was Australia that had acted unreasonably. If Australia, in 2010, had not abruptly rejected consensus on reform of the International Whaling Convention things may have been different. But Australia had said “it was now time to close the door on the Proposed Consensus Decision” on reform of the International Whaling Commission. Had Australia not done what it did the Commission would have been saved from the brink of collapse.

Professor Pellet later said that Australia was arguing that Japan’s Special Permits were the “fig leaves of commercial whaling”. But Australia and others, he said, replaced the objects and purpose of the Convention with “utterly ideological” opposition to whaling.

Tinned whale meat, results of Japan's scientific whale research. Image: Greenpeace

On the brink of collapse

More than once in this case it was inferred or stated that the International Whaling Commission was on the brink of collapse. Japan referred to the Kingdom of Denmark’s actions in unilaterally implementing a catch quota for Aboriginal subsistence whaling, because the Commission could not agree on their proposal for catch limits for 2013 and beyond. Denmark had indicated that it could “withdraw from the Convention before 1 January 2014”.

Japan went on to say that “if the hijacking of the Convention continues… soon there will be no whaling nations at the IWC… Soon there will be two competing international organisations…There will be a Whaling Commission and an anti-Whaling Commission”. Japan reflected again on this scenario in its final summing up.

What do we want? When do we want it?

Last week Australia asked that the Court “to adjudge and declare” that:

Japan is in breach of its international obligations in authorising and implementing its whaling program in the Southern Ocean
Japan refrain from authorising or implementing special permit whaling; and
Japan cease its whaling program immediately.

Australia also asked the Court to declare that Japan’s JARPA II whaling program is “not a program of scientific research” within the meaning of the Whaling Convention.

In summarising Japan’s argument in the case, the Deputy Minister for Foreign Affairs, Mr Koji Tsuruoka, thanked the Court and said “we have been able to present to the World the truth about Japanese scientific whaling”. He then went on to infer that if it was not possible for Japan to conduct its scientific whaling “the only way out is to leave”.

Mr Tsuruoka asked the Court “to adjudge and declare that the claims of Australia are rejected”.

When will we ever learn?

The Court will now retire to consider the vast amount of written and oral evidence before it. A Court official said that it usually takes the International Court of Justice four to six months to consider its cases.

That might not satisfy those who would like a decision soon to stop the next season of Japanese whaling in the Antarctic.

Tony Press receives funding from the Australian Government's Cooperative Research Centres Program. He is the CEO of the Antarctic Climate and Ecosystems Cooperative Research Centre.

This article was originally published at The Conversation.
Read the original article.

Antarctic marine park plan frozen out

fisheries, government, threatened species, waterways/wetlands, wildlife

Jul 172013

Original story by at The Age

An attempt by Australia to set up some of the world's largest marine reserves in Antarctica has been blocked at a meeting in Germany.

Fishing nations Russia and Ukraine questioned the legality of the move, according to Terje Lobach, chairman of the Commission for the Conservation of Antarctic Marine Living Resources.

More protection sought: A king penguin during sunset at its Auster rookery near the Australian research station of Mawson. Photo: AFP

Mr Lobach said that many nations in the organisation also had doubts about the size of one of the reserves, a 2.6 million-square-kilometre proposal for the Ross Sea.

The rocky passage of marine reserve plans led their main non-government advocate, the Antarctic Oceans Alliance, to say their future was in doubt before Tuesday's final session of the meeting in Bremerhaven.

Australia, France and the European Union put forward a network of seven reserves in waters covering 1.63 million square kilometres of eastern Antarctic waters, and the US joined New Zealand in proposing the Ross Sea reserve.

Advocates say they would give extra protection to some of the world's largest wild ocean areas, where species such as penguins, seabirds, seals and whales live largely unharmed.

Inside the commission, opposition to the reserves emerged eight months ago at its annual meeting in Hobart, and it was reinforced at an Antarctic Treaty meeting in May where a resolution of general support was scotched. Now at a rare special meeting of the commission, long-time Antarctic fishing nations are still holding out.

''The issue was raised, I can say, by Russia and the question was also raised by Ukraine, whether [the commission] really has the competence of establishing [marine protected areas],'' Mr Lobach said at a news conference.

He said many lawyers in the closed meeting spoke against Russia and Ukraine, and definitely said the commission had the power and mandate to establish protected areas in the high seas.

''The challenge is, of course, that we are working under consensus rule,'' Mr Lobach said. ''So we have to have everybody on board to have an agreement.''

An informed source told Fairfax Media that Russia did not believe other commission countries were ''behaving properly''.

But Steve Campbell, director of the Antarctic Ocean Alliance, said Russia and Ukraine's challenges to legality were groundless.

Commission executive secretary Andrew Wright said delegates were considering whether to open up some areas that were now closed to ''research fishing'' to demonstrate that the marine reserves system was not an attempt to exclude fishing.

''The commission … is still open to suggestions in terms of research fishing that might be conducted in areas that have been closed to fishing for several years,'' Mr Wright said.

Decision due on massive Antarctic marine sanctuaries

fisheries, government, waterways/wetlands, wildlife

Jul 162013

Proposed marine protected areas on the east Antarctic coastal region

Original story by Matt McGrath, BBC News

Negotiators meeting in Germany are set to decide on the establishment of the world's biggest marine reserves in Antarctica.

Scientists are hoping the plans for protected areas in the Ross Sea and in Eastern Antarctica will be supported.

But a previous attempt failed to get the necessary backing of all 25 members involved.

And there are worries that countries including Russia could again scupper the proposal.

The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is made up of countries with an interest in the Southern Ocean, and includes Australia, the US, the UK, China and Russia among its members. Any decisions taken require consensus among all parties.

This meeting in Bremerhaven has been called to deal specifically with proposals for the establishment of reserves that would ban fishing and protect species including seals and penguins. If successful the plans would more than double the area of the world's oceans that are protected.

The proposed protected zone in the Ross Sea is home to a large proportion of the world's Adelie penguins

Protecting penguins

The idea of creating marine protected areas has been around for several years - but when it came to a decision late last October, several countries including Russia, the Ukraine and China had reservations and the meeting ran out of time.

The US and New Zealand are again backing a proposal to create a marine protected zone in the Ross Sea with a total area of 2.3m sq km, making it the biggest in the world.

According to Andrea Kavanagh, director of the Pew Charitable Trusts' Southern Ocean campaign, this would have a major benefits for a range of species.

"While it is called the Ross Sea, a portion of it is frozen solid 365 a year and provides a critical habitat for hundreds of species of birds, mammals, fish and invertebrates including 38% of the world's Adelie penguins and 26% of the world's Emperor penguins," she said.

Another proposal from Australia, France and the European Union would create protected areas in East Antarctica covering around 1.63m sq km.

Australia's minister for environment, Mark Butler MP, said the East Antarctic proposal would be a significant undertaking but would be about more than just protecting species.

"The MPA also includes scientific reference areas where we can measure long term changes and natural variability - essential pieces of information to ensure the conservation of key features and the sustainability of fishing in the region," he said.

Fishing is a big sticking point with species like krill and patagonian toothfish proving highly lucrative for boats from a range of countries, including South Korea, Norway and Japan.

There has been rapid growth in fishing for Antarctic krill driven by demand for Omega-3 oil supplements

In for the krill

The tiny shrimp like Antarctic krill are a key element of the ecosystem, as they are part of the diet of whales, penguins, seals and sea birds.

However demand for krill has risen sharply in recent years thanks to growing interest in Omega-3 dietary supplements.

In the months since the last meeting in Tasmania, diplomats have been working hard to stress the scientific case for ending fishing in these regions of Antarctica.

"There were a number of issues raised by countries including China, Russia and the Ukraine, they related to issues such as access to fishing and there were questions about the science," Bob Zuur, from campaigners WWF.

"The proponents have heard those concerns and have prepared detailed responses - we expect that those issues have now been addressed."

Environmentalists are worried that there may be attempts at a compromise, with a proposal from Norway for what's termed a "sunset clause".

Supported by Russia and Japan it would mean the protected areas in the East Antarctic would be reviewed in 2064 and the Ross Sea in 2043. Campaigners say that this is an unusual idea, given that protected areas on land or in the seas are usually designated in perpetuity.

If the meeting doesn't come to a decision or it is likely that unanimity can't be achieved, it is possible that the meeting will refer the issue forward to CCAMLR's annual gathering towards the end of this year.

Robotic Frogs Help Turn a Boring Mating Call into a Serenade

Interest, wildlife

Jul 162013

Original story from the University of Texas

AUSTIN, Texas — With the help of a robotic frog, biologists at The University of Texas at Austin and Salisbury University have discovered that two wrong mating calls can make a right for female túngara frogs.

The “rather bizarre” result may be evidence not of a defect in the frog brain, but of how well frogs have evolved to extract meaning from noise, much the way humans have. The research, which was published last month in Science, may also provide insight into how complex traits evolve by hooking together much simpler traits.

When choosing a potential mate, female túngara frogs listen to the sounds of the male calls, which are based on a pattern of “whines” and “chucks.” If visible, the sight of the male frogs inflating their vocal sacs adds to the appeal of the calls. It makes a whine more attractive, though still less attractive than a whine-chuck, and it makes a whine-chuck more attractive still.

In an innovative experiment, biologists Michael Ryan and Ryan Taylor played around with those visual and auditory signals. They took a recording of a basic whine, then added a robotic frog that inflated its vocal sac late. They ran a parallel experiment with a chuck that arrived late relative to the whine.

On their own neither the late vocal sac expansion or the sluggish chuck added to the sex appeal of the whine. In both cases it was as if the frog had just whined.

When the late cues were strung together, however, something extraordinary happened. The vocal sac “perceptually rescued” the chuck and bound it together with the first part of the whine-chuck call. The resulting signal was as attractive to the female túngara frogs as a well-timed “whine-chuck.”

“It never would happen in nature, but it’s evidence of how much jury-rigging there is in evolution, that the female can be tricked in this way,” said Ryan, the Clark Hubbs Regents Professor of Zoology in the College of Natural Sciences at The University of Texas at Austin.

Ryan compared the phenomenon to what’s called a “continuity illusion” in humans. If loud enough white noise is played in between a pair of beeps, humans will begin to perceive the beeps as a continuous tone. It’s not fully understood why this happens, but it’s probably a byproduct of our brains’ useful ability to filter out background noise.

Túngara frogs are challenged by an auditory world similar to what confronts humans in noisy environments (what’s called the “cocktail party problem” by cognitive scientists). At breeding choruses there is a lot of noise and cross talk, with sounds and images of several males reaching the female at different times. The females need to extract meaningful information from all of that. Ryan said it’s plausible the neural mechanisms that enable them to correctly parse these stimuli in nature are being hijacked by this artificial scenario.

“We need to be able to hook things together perceptually in unexpected ways to extract meaningful stimuli from a lot of noise,” said Ryan. “So what we think is happening here is that the vocal sac, the visual cue, is working kind of like the white noise, giving perceptual continuity between these two sounds, binding the temporally displaced whine and chuck together.”

Ryan said that although the frogs’ aggressive search for meaning leaves them open to being tricked by clever researchers, it could also enable more flexibility in complex situations. He believes it may have a much longer-term evolutionary advantage as well.

“It’s an example of how complex traits could emerge from simpler ones,” he said. “In this case there’s no obvious advantage to these two behaviors being hooked together in this way, but think of how you can take a muscle and move its insertion on the bone and have a great influence on speed. You didn’t get the evolution for these bones and muscles all at the same time, but just by making a change or adding a muscle, now you change the functional coupling. You end up with something really complex, but it evolved in a really simple way. I think in this case we may be seeing an example of how that could happen.”

R.C. Taylor is an associate professor of biology at Salisbury University in Maryland.

For more information, contact: Daniel Oppenheimer, College of Natural Sciences, 512 745 3353; Michael Ryan, School of Biological Sciences, mryan@utexas.edu.

Baby alligator among 23 animals stolen from Australian Reptile Park

Interest, wildlife

Jul 152013

Original story at news.com.au

THIEVES stole 23 animals including an alligator from the Australian Reptile Park overnight.

Police were called to the facility on the Pacific Highway, Somersby, following reports of a break and enter about 11am.

Elvis the saltwater crocodile gets his lunch at the Australian Reptile Park in Somersby. Photo: Sam Ruttyn

Staff told police approximately 23 various reptiles were allegedly stolen from the park including dragons, lizards and a baby alligator 20cm long.

Earlier reports that Elvis, a five-metre saltwater croc, who featured in the Daily Telegraph's GI Journo section on Saturday, had been stolen, are not true.

There are concerns for the reptiles as some are sensitive and require high maintenance, and without proper care there is a significant risk of them not surviving.

Australian Reptile Park senior curator Liz Vella said they were unsure exactly which animals and how many were missing.

``We haven't been able to get into the park to do an animal count because the police are still taking fingerprints and investigating,'' she said.

She said the animals stolen were all part of the park's educational collection.

``These are the ones we take out to show our visitors,'' she said.

``They are very rare and specialised - they aren't dangerous but they need our care. A lot of them are also used in our regional breeding programs with other zoos.''

Ms Vella said the animals taken were a mix between exotic and native and included geckos, lizards and a baby alligator.

``We're devastated. We love these animals like they are our own,'' she said.

``They all have their own personalities and we are really worried about them.

Staff were alerted to the security breach after their surveillance cameras detected the intruders between 11pm and 12am.

Police are appealing to any witnesses to the incident, or anyone who may have any information about the reptiles to contact CrimeStoppers on 1800 333 000.

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