Among nature's more interesting wonders is the ability of many lizard species to escape their predators. When caught in a vulnerable position, they simply drop their tails, leaving the twitching body part to distract the predator as they scamper to safety.
But, says Gary Gillis, a biology professor at Mount Holyoke College, the lizards lose significant mobility and agility in return for this life-saving natural escape mechanism.
Up to 50 percent of some lizard populations seem to have traded part of their tails in exchange for escape, according to Gillis. While the tails typically grow back in three to six months, Gillis wondered how the loss might impact a branch-hopping, tree-dwelling lizard’s mobility and ability to survive in the interim. Teaming up with undergraduate student Lauren Bonvini, he began recording lizard leaps to observe how well the reptiles coped without their tails. The results are being published February 13 in The Journal of Experimental Biology (http://jeb.biologists.org/).
Constructing a jumping arena from boxes and fine sandpaper, Gillis and Bonvini gently encouraged arboreal Anolis carolinensis (anole) lizards to launch themselves from an 11-centimeter-high platform while filming the animals’ jumps. The lizards performed well, launching themselves by pushing off with their back feet and landing gracefully, covering distances ranging from 14.9 to 29.9 centimeters.
But how well would the animals perform without their tails? After holding the lizards' tails to encourage them to drop them, just as they would with a predator, Bonvini then persuaded the tailless reptiles to jump while Gillis filmed them. As soon as the first animal took to the air, Gillis knew something was different.
"It looked weird," he said. "The animals became blurred as they jumped."
Replaying the animal's jump in slow motion, the team could see that it was tumbling backwards, out of control, as its tail stump flailed. Filming other tailless anoles, four backflipped out of control, although two others seemed to manage their trajectories better.
Teaming up with Duncan Irschick of the University of Massachusetts, Amherst, to analyze the reptiles’ leaps, Gillis could see that everything about the tailless lizards’ take-off was exactly the same as it had been before they lost the appendage – until they left the jump stage. The lizards then began flipping backwards by more than 30 degrees; some tumbled so far that they landed on their backs. The team also realized that when the lizards with whole tails took off, they raised the base of their tails as the rest of the appendage trailed along the ground, as if it was somehow stabilizing the take-off.
"If jumping and landing are important for lizards, they are clearly compromised after losing their tails. Coordinated landing on a branch is out of the question when spinning backwards," said Gillis. Escaping lizards pay a significant ecological cost for their life-saving quick-release system, he concluded.
So how do the lizards use their tails to ensure a safe touchdown? Gillis isn’t sure whether they push down with their tails at take-off to prevent themselves from spinning, or whether the trailing tail passively stabilizes the animal’s departure. He is continuing his research to determine how lizards adjust to life without their tails, with differential degrees of tail loss, and after the tails have grown back.Related Links:
Full text of the article is available ON REQUEST. To obtain a copy contact Kathryn Knight, The Journal Of Experimental Biology, Cambridge, UK. Tel: +44 (0)1223 425525, or email email@example.com
Gary Gillis | Newswise Science News
New catalyst controls activation of a carbon-hydrogen bond
21.11.2017 | Emory Health Sciences
The main switch
21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
21.11.2017 | Physics and Astronomy
21.11.2017 | Physics and Astronomy
21.11.2017 | Life Sciences