- July 31st, 2012
- in Yachting
One evening not long ago, I was enjoying dinner at a local outdoor restaurant. As I took in the tropical ambiance, I noticed a small moth flying around a light on the wall. After a few circles, it landed just a few inches from the fixture. In the blink of an eye, the moth disappeared, snatched from its perch by the lightning-quick strike of a small cream-colored lizard. Just as quickly, it retreated to the safety of an overhang, the fluttering moth gripped firmly in its jaws.
I had just witnessed the nighttime foray of the wood slave, or tropical house gecko. This small, innocuous lizard lives quite happily with humans. It fact, houses are its favoured habitat. Wherever there is an outside light that attracts insects, the wood slave is not far away. It easily scampers up a vertical wall or upside down on the ceiling.
The gecko owes this remarkable ability to its toe’s pads. Expanded toes look like little suction cups. However, instead of suction, the toes are covered with tiny hair like structures called setae that grip smooth surfaces with what scientists define as van der Waals forces. The setae allow the gecko to adhere to surfaces as smooth as glass. That’s why they can fly up a wall or sleep suspended from a ceiling. In fact, recent scientific studies reveal remarkable additional properties of gecko toes. For example, natural body chemicals called phospholipids help speed the attachment process of the toes. Such discoveries often lead to useful products for humans.
Geckos have a worldwide distribution wherever the climate is warm. In fact, there are nearly 1,500 known species. In addition to our house gecko, there are approximately a half dozen native species in the Virgin Islands. They range from the turnip-tailed gecko, the second largest in the world, to the diminutive Virgin Gorda dwarf gecko, one of the smallest vertebrate animals on land. While most of the native geckos are secretive and rarely seen, the house gecko is quite conspicuous and often seen at night.
Our house gecko belongs to the genus Hemidactylus, and is native to West Africa. No one knows for sure, but it’s presumed they arrived several centuries ago as scaly stowaways on slave ships. Since their arrival, they have adapted well and are now common throughout the American tropics including much of the southern US. Their impact on our native fauna is probably minimal. Just to be sure it might be useful to conduct some studies on their ecology and behavior. Meanwhile, we can probably assume the gecko’s association with human settlements and their presence here for several centuries means their impact on native ecosystems is minor. Of course, understanding a bit of gecko life history might help our evaluation of these little critters.
All geckos are primarily insectivores. That’s why our wood slave hangs around lights. Best of all, they eat mosquitoes. If you observe a wood slave for any length of time, you will notice that they can change colour. They can vary from nearly white to dark grey and brown with darker markings. Colour changes may signify mood, perhaps anger at another gecko, physical condition, or simply an attempt at camouflage.
One interesting feature of all geckos is the lack of an eyelid. Instead, the eye is covered by a transparent membrane that is cleaned by licking. A gecko cleaning its eye with the tongue has been photographed many times and has even made it into the world of advertising. Ever see the Geico Gecko commercial?
Hobbyists occasionally keep these little lizards as pets. They are generally easy to care for, given the basics of warmth, humidity, and plenty of small insects. However, handling them is an absolute no no. Geckos have a very delicate thin scaly skin. Holding one would be a bit like trying to hang on to a piece of wiggling wet tissue paper. It is almost impossible without tearing the skin. Such an injury could be fatal to a captive specimen. In addition, when threatened, the gecko can drop its tail in a process called autotomy. It will eventually grow back. As lizards go, geckos can be quite vocal. Their call is best described as a “chirp” that may sound more like an insect.
Since the wood slave has been associated with human settlements for a long time, it is not surprising that superstitions and fears have arisen. Many people are afraid of these innocuous animals. They are sometimes attributed with spiritual characteristics, usually bad. One superstition says that if a wood slave falls and lands on a young lady, she will become pregnant. While such an event may have occurred in the past, it is doubtful the gecko was to blame.
Rather than with fear, the wood slave should be treated as an interesting part of our natural world. They are completely harmless. In fact, any lizard that eats insects, especially mosquitoes, should be protected and considered beneficial. Next time you are sitting outside near a light, pay attention and look for our denizen of the walls. Listen for the chirps and be happy that there will be a few less mosquitoes to spoil your evening.