Whilst small, comical geckos are more common at our Thai villa, wriggling upside down across the ceiling as if they have imbibed rather too much of the local rice moonshine,  their larger counterpart, the Tokay Gecko, also likes to make the occasional appearance. This one kindly helps out as a natural and ecologically friendly mosquito depleter.

This is the second largest species of gecko in the world...and has a rather gaudy red-spotted uniform on in honour of this! Read more on the gecko, both factual and folkloric, at our Gecko Villa gecko page.

It is quite commonly known that geckos sometimes defend themselves from an attacker through shedding their tail. However, it seems the process is more convoluted than originally expected, and that this defense mechanism may shed light on the human response to spinal chord injury.

Scientists from Clemson University & the University of Calgary have found that the self-severed tails of some geckos show a complex pattern of repeating movements to distract the predator. The research brings to light data about animal nervous systems - information that may lead to new insights into spinal injury in humans.

Evolutionary biologists Timothy Higham of Clemson and Anthony Russell of Calgary presented their findings in an article enticingly called called “Flip, flop and fly" - with a more scientific tagline detailing the study's investigation into "modulated motor control and highly variable movement patterns of autotomized gecko tails.”

Higham explains that "autotomy" is the process by which an appendage is deliberately shed by an animal. “A number of reptiles, amphibians, mammals and many invertebrates developed the defense mechanism over time. Some geckos’ severed tails can move repeatedly, allowing the gecko to escape and grow a replacement". Conjuring up a confused image of the popular insurance symbol, he notes that "It’s like a gecko’s personal injury insurance policy.”

Higham and Russell explored how the tail continues to function, using motion to entice a predator while the gecko escapes. The research shows that a severed tail of leopard gecko makes four to eight rhythmic moves per second with one or two complex movements – dramatic flips or lunges – during the first 50 seconds of its separation.

How does the tail do it? The scientists theorize that central pattern generators in the tail control the actions. Central pattern generators are made up of a network of nerve cells that enable a repeatable pattern of behavior, such as chewing, walking, flying. The gecko study adds to the evidence that central pattern generator networks can function without being linked to a brain or central nervous system. The findings present the prospect that human central pattern generators could play a role in restoring motion to people with spinal injuries.

“The autotomized gecko tail may be an excellent model for understanding the spontaneous activity that is sometimes observed following partial and complete spinal cord injury,” conclude Higham and Russell.