Scientists thought that sawfish used their saw to probe the sea bottom for food. But a Cairns researcher has found that these large (5 metres or more) and endangered fish actually use the saw to locate and dismember free-swimming fish – using a sixth sense that detects electric fields. She’s in Melbourne this week as a winner of Fresh Science. [click to continue…]
Issued on World Oceans Day
Southern bluefin tuna can’t even have a quiet snack without CSIRO researchers knowing. They’ve developed a way of tracking when the tuna feed and also where, at what depth, and the temperature of the surrounding water.
It’s the first time anyone has been able to observe the long term feeding habits of migratory fishes directly and the information is transforming our understanding of these highly sought after ‘Porsches of the sea’.
Dr Sophie Bestley and her colleagues at CSIRO’s Wealth from Oceans National Research Flagship surgically implant miniaturised electronic “data-storage” tags into juvenile fishes off the coast of southern Australia. [click to continue…]
Dr Fiona Hogan is DNA fingerprinting Australian owls with the help of feathers and a keen public.
Her work is transforming our understanding of the night life of owls, normally notoriously secretive.
From a single feather, this Deakin University researcher can determine the species, sex, and identity of individual birds. She has already found a pair of powerful owls who have mated together for at least 10 consecutive years, and that those breeding in urban areas are typically more closely related than those which breed in the bush. [click to continue…]
Certain small reef fish use wing-like fins to ‘fly’ underwater, allowing them to cruise at speeds equivalent to tuna, a team of Australian and US researchers has found. The design of the fins has drawn the attention of underwater submersible designers and the US Office of Naval Research.
Scott Cummins and his colleagues at The University of Queensland have uncovered a potent mix of chemicals which acts like a cross between Chanel No 5 and Viagra-but only if you are a sea slug.
Why are some males faithful, stay-at-home partners while others sleep around, with no strings attached? In mountain brushtail possums, it turns out to depend on how disturbed their home is.
Armidale sheep put to the test in a complex maze
Sheep are smarter than we think. They can learn and remember according to CSIRO researchers from Armidale in NSW. The team is working to identify and breed smarter sheep as part of their work to improve animal welfare and production.
Caroline Lee, a member of the animal welfare team at the F D McMaster Laboratory, has developed a complex maze test to measure intelligence and learning in sheep, similar to those used for rats and mice.
“Using the maze, we have already shown that sheep have excellent spatial memory and are able learn and improve their performance. And they can retain this information for a six-week period,” Dr Lee said.
“The aim of our work is to identify intelligent sheep, by accurately measuring how they perform in the maze. This will improve animal welfare by enabling us to select animals that are better suited to our changing farming systems.
“With the move towards more automated farming, being able to select smarter sheep will make them easier to look after and monitor on the farm. For instance, the latest methods for weighing sheep involve them walking independently across a weighbridge.”
“Smart sheep can do this readily. Such technology makes for happier sheep, and increased productivity,” she said.
The maze uses the strong flocking instinct of sheep to motivate them to find their way through. The time it initially takes an animal to rejoin its flock indicates smartness, while subsequent improvement in times over consecutive days of testing measures learning and memory.
Caroline is one of 13 Fresh Scientists presenting their research to the public for the first time thanks to Fresh Science, a national program hosted by the State Library of Victoria. One of the Fresh Scientists will win a trip to the UK courtesy of the British Council to present his or her work to the Royal Institution.
The research is part of a collaborative project between CSIRO, Institut National de la Recherche Agronomique (INRA) France and University of Western Australia and is funded by the French-Australian Science and Technology Program.
Sheep waiting to enter the maze, with Caroline
A sheep entering the maze
Caroline observing a sheep in the maze,
The Australian lungfish-one of the world’s oldest fishes and related to our ancient ancestors-may have been viewing rivers in technicolour long before dinosaurs roamed the Earth.
Recent work by postgraduate student Helena Bailes at the University of Queensland has found these unusual fish have genes for five different forms of visual pigment in their eyes. Humans only have three.
Night and day (colour) vision are controlled by different light sensing cells known respectively as rods and cones. Humans have a single type of rod and three types of cone, each containing a different pigment gene tuned to red, green and blue wavelengths. Lungfish possess two additional pigments that were lost in mammals, Bailes says. They are tuned to longer wavelengths than in most other fish.
“Lungfish are very large, slow-moving fish, so vision was always assumed to be of little importance” she says. “This work may change that theory.”
Lungfish are ‘living fossils’ unchanged for over 100 million years. The Australian species (Neoceratodus forsteri) is the most primitive of the living lungfishes. It is a threatened species protected from fishing which lives in only a handful of rivers in south east Queensland.
“The only way to find out how the first creatures on land saw the world is to look at their closest living relative: the Australian lungfish,” Bailes says.
The photoreceptive cells, which house the visual pigments, are bigger in lungfish than for any other animal with a backbone. This probably makes them more sensitive to light.
“We keep discovering ways in which these animals are quite different from other fish,” Helena Bailes says. “Their eyes seem designed to optimise both sensitivity and colour vision with large cells containing different visual pigments.”
She now is hoping that behavioural research can find out how these fish are using their eyes for colour vision in the wild.
“We may then learn what Queensland rivers look like to some of their oldest inhabitants, before those inhabitants are wiped out,” Bailes says.
Helena is one of 13 Fresh Scientists who are presenting their research to the public for the first time thanks to Fresh Science, a national program sponsored by the Federal and Victorian Governments. One of the Fresh Scientists will win a trip to the UK courtesy of the British Council to present his or her work to the Royal Institution.
|Helena working in her laboratory||Composite image, clockwise from top: Helena in the lab, Australian lungfish, retinal photoreceptors of lungfish, a retinal ganglion cell leading from the eye to the brain in lungfish||Australian lungfish|
Box jellyfish are capable of moving several kilometres a day, but seem to stay within a relatively short stretch of beachfront. Those are some to the initial findings of a young researcher in North Queensland, who is undertaking the first detailed study of the movements of the potentially lethal animals.
Matt Gordon of the Tropical Australian Stinger Research Unit at James Cook University in Cairns is using the latest ultrasonic technology to track the jellyfish. He aims to make Australia’s tropical beaches safer by developing a computer model capable of predicting where and when they will occur.
“There are several long held theories regarding where box jellyfish are found and why they move from one area to another,” Gordon says. “But until now there has been limited evidence to support them.
“For instance, as early as the 1960s it was suggested that box jellyfish swim up creeks towards the end of the season to reproduce. But until we followed a large, sexually mature individual up an estuary near Tully in April of this year, there was no hard data on this.”
In order to record their movement patterns, each box jellyfish is fitted internally with an ultrasonic tag using a type of surgical glue called Histoacryl. Each tag emits a unique signal that can be heard underwater using a hydrophone. It is now possible to track the movement patterns 24 hours a day, 7 days a week using new submersible ultrasonic receivers developed in the US.
By collecting data from four different locations, Matt Gordon intends to develop a model that can be applied throughout the tropics. It is anticipated that such a model will be of benefit to local councils and the tourism industry by allowing stinger enclosures, tourist attractions and resorts to be placed in safer areas.
Matt is one of 13 Fresh Scientists presenting their research to the public for the first time thanks to Fresh Science, a national program hosted by the State Library of Victoria. One of the Fresh Scientists will win a trip to the UK courtesy of the British Council to present his or her work to the Royal Institution.
Tree frogs defy the trend of urban decline
Central Melbourne used to be a Mecca for frogs, but now there is only one species left.
Southern brown tree frogs can still be heard calling to attract females for mating in parks throughout inner Melbourne, including the Royal Botanic Gardens and Fitzroy Gardens.
A survey conducted at 104 ponds across Melbourne found a total of nine frog species, but revealed the southern brown tree frog to be the sole inner-city survivor.
An important factor in the loss of other frog species from central Melbourne is the steep walls of bluestone or concrete surrounding many ponds, according to Dr Kirsten Parris of Deakin University and the Royal Botanic Gardens Melbourne.
“Most frogs around Melbourne can’t climb vertical surfaces, so young frogs would become trapped in these ponds and drown,” Kirsten said. “But the southern brown tree frog can climb, using its large sticky toes – that’s what makes this frog special.”
A second reason for the decline of frogs in the city is that urban ponds are isolated from each other by roads, houses and factories. If a population dies out, other frogs cannot arrive safely to start a new population.
“Frogs cannot cross busy roads without being squashed. I found that the number of frog species at a pond drops as the number of roads around the pond increases” Dr Parris said.
“There are two simple things we can do to bring more frogs back to central Melbourne – replace steep pond walls with gradual slopes, and use a carefully-designed program to reintroduce the tadpoles of some species that used to live there.
“This way, late-night revellers in the city will be able to hear a varied chorus of frisky male frogs calling to woo their women and perpetuate the species in an unlikely urban habitat.”
Kirsten is one of 15 early-career scientists presenting their work to the public and media as part of Fresh Science 2004. The scientist who best meets the requirements of the program will win a study tour to the UK courtesy of British Council Australia.
Sporting technology used on lizards to watch them run.
The same camera that analysed the bowling action of Sri Lankan cricketer Muttiah Muralitharan is being used to study how dragon lizards can escape a bigger, faster predator, the goanna.
“It’s all in the running action,” says zoologist, Chris Clemente from the University of Western Australia. His work has shown that lizards have adapted their locomotion to fit with their habitats. For example, the dragon lizard can swing its leg around in almost a full circle which gives it an advantage in woody habitats with lots of obstacles.
Australia has the highest diversity of lizards in the world. They are a major part of our environment. Yet, despite this rich abundance, we don’t know much about them, says Chris, one of 15 early-careers scientists presenting their work to the media as part of the national Fresh Science competition.
What’s more, he says, lizards are direct descendents of dinosaurs. “If we understand modern day lizards we may also be able to unlock secrets of the past,” he said. “For example, the ancient seven-metre goannas may have had a more upright style of running making them faster runners than humans.”
Chris is using motion-analysis cameras to create a three dimensional model of the lizards running in virtual space. When combined with information about the habitat and body shape of these lizards, it begins to paint a picture of the lizard world.
“We may then be able to use this picture to predict how extinct reptiles moved and what habitat they lived in,” Chris said.
Goannas are a particular focus of his work. An invasion of these lizards from Asia 6 million years ago has resulted in 27 different species spread right across Australia. They can be found living in diverse habitat, from open deserts to tropical rainforest.
“They also vary in size. The smallest goannas are about the size of your thumb and the largest stretch over two metres,” he said. “No other group of animals shows such variation in body size, and my research is looking at why this group of lizards has been so successful.
“Larger lizards like goannas often hunt smaller lizards like dragons, and my motion research can help predict who would win such a predator-prey survival battle,” he said.
“I have found that the larger goannas will outrun the smaller dragons every time. But the dragons often get away because of their greater manoeuvrability.”
Chris got interested in this research after reading about the study of how ostriches run. Being bipedal, the research was comparing their gait with that of humans. With a passion for lizards, especially the giant lizards from prehistoric times, his honours project began by looking at dragon lizard locomotion. Moving on to goannas for his PhD, he got thinking about who would back in a race – goanna or lizard?
Ctenophorus Cristatus running upright on two legs (bipedally)
Goanna marked up ready for action
Puberty blues: goby fish choose their sex to find a mate
New research on the Great Barrier Reef has revealed that some young reef fish can choose when they mature and which sex they want to be when they grow up. [click to continue…]
What can bees teach us about speed shopping? Does trading off speed for accuracy pay?
Bumblebees have been shown to have very fine colour vision – which they can use to find up to 5,000 flowers a day. [click to continue…]
Scientists agree: some people are universally gorgeous. Studies in evolutionary biology show that few things are more advantageous to success than being attractive, since good looking individuals leave more offspring than their unattractive contemporaries. [click to continue…]