22 June 2013

Yellow-bellied House Gecko – Dhahran Hills

My daughters found a Yellow-bellied House Gecko Hemidactylus flaviviridis in the upstairs bathroom of our house last night and called me to see it. It was a small Gecko, measuring only about 15 centimetres long including the tail. I managed to catch it and took a few photographs before releasing it on the outside of our house. They occur through parts of the Arabian Peninsula including Saudi Arabia as well as Afghanistan, Egypt, Ethiopia, India, Iran, Iraq, Nepal, Pakistan and Somalia and can vary their body colour depending on the time of day, being greyish, olive or brown, patterned with indistinct bands on the back and yellowish on the underside. During the day, the gecko is usually much darker in colour, with contrasting, chevron-shaped bands on the body with the toes having broad pads and small claws. They are associated with man-made structures such as houses, but during the day, they retreat to undisturbed crevices and other such hiding places coming out at night to feed primarily on insects. They can climb vertical walls and walk on ceilings which is achieved by having specialised toe pads, which are covered in small scales called ‘scansors’ which can have up to 150,000 microscopic, highly branched, hair-like structures, known as setae, which form hundreds of saucer-shaped ‘end plates’. This gives the Gecko an enormous surface area in relation to its body size, enabling it to grip all kinds of surfaces. This species of Gecko has particularly large and sensitive eyes, with pupils which open-wide at night to let in maximum amounts of light, giving it excellent vision in the dark. The pupils contract to vertical slits during the day to protect the retina from harsh sunlight, while the eyelids are fused to form a transparent cover for additional protection. Any dust or debris in the eye is licked away by the gecko’s extremely mobile tongue, which must have been useful recently as the weather has been very windy causing large amounts of dust to be blowing around.