Backyard visitors

When these lizards put themselves in the spotlight, you can stay at home and catch a show, writes LEONARD CRONIN

There’s been an explosion of geckos around our house this year. Their antics during the warmer months provide us with nightly entertainment as they congregate around lights, dashing after insects and spiders and fending off rivals. There’s lots of tail-waving and chasing as the largest geckos try to hang on to their territory, accompanied by their noisy chuck-chuck-chuck calls as they assert their dominance.

Asian house geckos are increasingly common in Australia, having spread across the country from tropical Queensland. Living almost exclusively in houses where food is plentiful and easy to catch, they hide behind wall hangings and in cracks and crevices, and seem to be outcompeting our native house geckos, causing some concern among biologists.

Hitchhiking as stowaways on cargo ships, Asian house geckos have the widest distribution of any lizard in the world. They reach about 11cm long, and are similar to our native house geckos, but can be distinguished by the spines running down the sides of their tails.

It’s fascinating to watch them defy gravity, climbing up windows and running upside down across the ceiling. It used to be thought that their large toe pads had tiny suction cups, but they are, in fact, covered with millions of microscopic bristles. These are pressed so close to the given surface that weak bonds form between the bristles and the surface molecules. Although the force attracting each bristle to the surface is minute, there are so many bristles that the cumulative effect is great enough to ‘glue’ the gecko’s feet firmly to the wall or ceiling.

In the tropics, Asian house geckos breed year-round, with each female producing two relatively large white eggs every 4–6 weeks. Sometimes you can see the eggs through the female’s translucent skin.

In subtropical and more temperate areas, they cease breeding and become quite lethargic during the winter months. Until spring returns, we will miss their cheerful calls and 3D capers.

Len gardens in the Northern Rivers, New South Wales