Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Jamaican lizards' shows of strength mark territory at dawn, dusk

01.09.2008
Birds and others sing; anoles are first species known to mark time through visual displays

What does Jack LaLanne have in common with a Jamaican lizard?

Like the ageless fitness guru, the lizards greet each new day with vigorous push-ups. That's according to a new study showing that male Anolis lizards engage in impressive displays of reptilian strength -- push-ups, head bobs, and threatening extension of a colorful neck flap called a dewlap -- to defend their territory at dawn and dusk.

The lizards are the first animals known to mark dawn and dusk through visual displays, rather than the much better known chirping, tweeting, and other sounding off by birds, frogs, geckos, and primates.

Terry J. Ord, a postdoctoral researcher at Harvard University's Museum of Comparative Zoology and at the University of California, Davis, describes the Anolis lizards' unusual morning ritual in a forthcoming issue of the journal American Naturalist.

"Anoles are highly visual species, so in that sense it's not surprising that they would use visual displays to mark territory," Ord says. "Still, the finding is surprising because these are the first animals known to use non-acoustic signaling at dawn and dusk."

Ord studied four species of Jamaican forest lizard: Anolis lineatopus, Anolis sagrei, Anolis grahami, and Anolis opalinus. Female anoles establish small territories allowing access to food and other resources, while males stake out larger territories allowing them access to several females. The males spend much of the day sitting on tree trunks and displaying head motions, push-ups, and dewlap extensions, all to warn other males away from their territory.

Ord carefully located and videotaped individual males at different times of day, from before dawn to dusk. In all four species, he found distinct peaks of activity at daybreak and for about two hours afterward, and again just before dark.

"These patterns have remarkable parallels with the dawn and dusk choruses reported for many acoustically communicating animals," Ord says.

As in many species of birds, anoles leave their daytime perches at night to find safe shelter, since both birds and reptiles are frequently targeted by nocturnal predators.

"The dawn chorus may be a way of communicating having survived the night," Ord says. "If in the morning a bird doesn't hear its neighbor, or an anole doesn't see its neighbor, it may be an opportunity for the animal to expand its territory."

While ornithologists disagree on the exact reasons why birds chorus at dawn and dusk -- competing hypotheses propose everything from territorial defense to favorable environmental conditions to manifestations of circadian rhythms -- Ord says his work suggests male anoles use their morning displays primarily to mark territory.

"All of these behaviors are displays of physical vigor," Ord says. "As in humans, if an anole can do many of these push-ups it shows that he is in prime physical condition. These displays of strength help avert actual physical confrontations between male lizards, which can be very fierce and destructive."

Ord's work may open the doors to further study by ornithologists, herpetologists, and others seeking evidence of non-acoustic dawn and dusk signaling among other species.

Steve Bradt | EurekAlert!
Further information:
http://www.harvard.edu

Further reports about: Anolis Jamaican Jamaican lizard Ord anole frogs geckos lizard lizards push-ups territory visual species

More articles from Life Sciences:

nachricht Molecular Force Sensors
20.09.2017 | Max-Planck-Institut für Biochemie

nachricht Foster tadpoles trigger parental instinct in poison frogs
20.09.2017 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>