When a tiny lizard is moved away from his territory and placed in a new "mystery" location, can he find his way back? If so, how?
Yellow-bearded anoles are territorial species, with males staking out a tree as home turf. Researcher Manuel Leal, a behavior ecologist from University of Missouri who studies anoles in Puerto Rico, attached miniature tracking devices to 15 male anoles, walked them to a new site while disorienting them, and tracked them to find out if they could make their way back to their home-turf tree within 24 hours.
What happened is surprising and creates a new set of questions about the abilities of animals to navigate despite overwhelming odds that should leave them lost for good. This short documentary by HHMI BioInteractive with Days Edge Productions follows Leal in the field as he, in turn, follows the anoles.
Other animals can find home, too
The experiment focused on yellow-bearded anoles, but this impressive ability isn't exclusive to these tiny lizards.
Homing pigeons are also famous for this ability. And a new theory for how homing pigeons find their way home is that they use sound waves that emanate from the Earth itself.
Popular Science describes the theory put forward by U.S. Geological Society geologist John Hagstrum: "The idea is that pigeons use these low-frequency infrasound waves to generate acoustic maps of their surroundings, and that's how they find home even when they're released miles from where they dwell. The theory not only explains how pigeons make their way home almost every time, but why they sometimes get lost. (High winds, supersonic jets and various other phenomena can disrupt these infrasound waves, disorienting the birds and setting them on a false course for home.) So while it's by no means conclusive, this new theory seems at first glance a very tidy way of explaining a mystery that has baffled avian biologists for generations."
Might anoles also use such sound waves? Or could it be another sense that picks up the cues to lead them home again, even when they're quite lost?
The research that will give us the answers to these little lizards' navigation abilities might also help us unravel other mysteries about animal senses.
"Leal says there are many reasons why anoles are a great system for studying evolution," explains the University of Missouri website. "There are hundreds of species, they have colonized a diversity of habitats, and they exhibit a wide range of complex behaviors."