Tasmanian tigers' brains yield clues
Once numerous across Tasmania, the Tasmanian tiger was branded a sheep killer by colonists in the 1830s and hunted to extinction. The last of its kind died in a zoo in 1936, and with it many of the secrets of the animal's life were lost.
Now, for the first time, researchers have performed neural scans on the extinct carnivore's brain, revealing insights that had been lost since the species went extinct.
"Part of the myth about them is what exactly did they eat, how did they hunt and were they social?" said Dr Gregory Berns, a neuroscientist at Emory University and lead author on the study, which was published in the journal PLOS One.
"These are questions nobody really knows the answers to."
With their slender bodies, long snouts and sharp teeth, Tasmanian tigers, also known as thylacines, looked as if they could be related to dogs, wolves or coyotes. But actually they are separated by more than 150 million years of evolution.
Dr Berns spent two years tracking down two preserved Tasmanian tiger brains. Their brains, like those of marsupials, are very different from those of placental mammals. The biggest difference is that they lack a corpus callosum, the part of the brain that connects the left and right hemispheres.
Enter the Tasmanian devil, a carnivorous marsupial that mostly scavenges for food, and one of the Tasmanian tiger's closest living relatives.
Dr Berns collected two Tasmanian devil brains, scanned them and compared them with the two Tasmanian tiger brains. He found that Tasmanian tigers had a larger brain, particularly the frontal lobes. This suggested that Tasmanian tigers were smarter than Tasmanian devils and used their cortex more for planning and decision-making. That, he said, further supported the idea that Tasmanian tigers were avid hunters.
Dr Berns said his research could change our understanding of these Australian predators. "Go back 100 years, people dismissed thylacines as stupid animals because they weren't fast moving," he said. But what he could see of their brains showed "they were probably quite intelligent".
Study of ants could lead to far better robots
Despite their tiny size, ants are sophisticated navigators that can find their way even while walking backwards, and these skills could help inspire better robots, scientists say.
The findings, published in the journal Current Biology, are based on a colony of desert ants that were studied to see how they navigated home while carrying pieces of a cookie.
SMALL STEPS, BIG ADVANCE
Understanding their behaviour gives us new insights into brain function, and has inspired us to build robot systems that mimic their functions.
PROFESSOR BARBARA WEBB, from the University of Edinburgh's School of Informatics, and co-author of the study on desert ants. Study of ants could lead to far better robots
Carrying small bits, they walked forward. But with larger pieces, they dragged them backwards towards their nest, occasionally dropping the food to check the sun's position and re-orient themselves.
Researchers said this practice of checking the environment and matching their progress against their memories of their surroundings shows the insects' mental capacity is more complex than previously thought.
"Ants have a relatively tiny brain, less than the size of a pinhead. Yet they can navigate successfully under many difficult conditions, including going backward," said study co-author Barbara Webb, a professor at the University of Edinburgh's School of Informatics.
"Understanding their behaviour gives us new insights into brain function, and has inspired us to build robot systems that mimic their functions."
Researchers say the ants' process could be useful to people, because it could help them develop new computer algorithms to guide robots. The research team included scientists from the University of Lincoln, Australian National University, and the French National Centre for Scientific Research.
Fishing for clues to solve fairy circle mystery
With its bone-dry grasslands and oppressive heat, the middle of the Namib Desert may seem like a strange place to go fishing. Yet, there researchers Jennifer Guyton and Tyler Coverdale were, standing in a sea of orange sand and brittle yellow grass with their 9m carp pole.
The two Princeton graduate students had swapped the hook with a camera so that they could investigate the scenery around fairy circles.
That is what scientists call the mysterious bald spots speckled across Namibia's grasslands. The rings are about 2m to 35m wide and are regularly spaced out in a hexagon or honeycomb pattern.
Fairy circles have long puzzled researchers as to their origins. But a new study published in the journal Nature seeks to offer some insights.
There is passionate scientific disagreement over how they arise. One side suggests that termites create the circles as they fight for dominance and resources. The other says that plants simultaneously assist and compete with their neighbours' roots, causing the vegetation to "self-organise" into the patterns.
The new study suggests both termites and plants may be responsible. And it has received mixed reviews from scientists entrenched in the dispute.
The two researchers tested the termite and plant explanations in a computer model, and found that either hypothesis could generate the fairy circle features. But when they tested both mechanisms together, the model revealed a second, smaller pattern hidden within the clumps of grass between the fairy circles. The next step was to confirm that this second vegetation pattern existed in nature. So the two researchers were sent to Namibia in 2015.
Ms Guyton said each of the grassy patterns was as different as fingerprints, but were mathematically similar. By comparing the photos with their model, the team verified that the second pattern did exist in the grass surrounding the Namibian fairy circles. That finding, they said, confirmed that their mathematics reflected reality and suggested that only by interacting together could insects and plants create the landscape that characterises Namibian fairy circles.