Round Island Day Gecko

(Phelsuma quentheri)

by Arlene, High School for Environmental Studies

Physical Description: At 28 cm long, The Round Island Day Gecko is the largest of 27 species of day geckos. The smallest day gecko is only about 8 cm long. Most day geckos are bright green in color. The Round Island Day Gecko is probably the dullest looking one of all. It lives on palm trees and is perfectly camouflaged against the brown bark of the main stem of the tree.

Close up of a Round Island day gecko foot. Notice the special scales for gripping smooth surfaces. Gecko breeding facility at the Jersey Zoo. 1979: The "denuded" habitat of Round Island at the beginning of the restoration project. 1989: Regeneration of native chloris grass on Round Island.

Special Adaptations: Geckos have special feet to help them climb up smooth surfaces. The flattened toes have elongated scales. A microscopic view would show thousands of tiny, hooked bristles that can hold on to any surface. This means they can easily climb up palm trees, as well as hide on the underside of leaves. They also have sharp teeth to penetrate the exo-skeleton of an insect. If attacked, Round Island Day Geckos have a unique way of defending themselves. The tail just drops off and lies moving around on the ground. Hopefully the enemy will pay attention to the tail while the gecko escapes. The stump quickly heals, and they will eventually grow a new tail.

Feeding/Diet: Round Island Day Geckos will eat any insects that land on the palm tree. They may try to move closer to their prey, or they will wait until it walks closer and grab it with its mouth. The gecko also eats pollen and nectar from the palm flowers. The gecko may also leave the palm tree to search for food such as fermenting fruit and ground-living insects.

Breeding/Reproduction: The breeding season is from February to September, but most eggs are laid in June. Each female lays about one or two eggs at a time. The eggs are sticky and can be placed on the underside of palm leaves, or under overhanging rocks for protection. Most females lay their eggs then leave them. The eggs are incubated for 58-104 days in the warm air. When they hatch, the offspring are fully equipped with their special feet so they can grip the nearest surface.

map Geographic Range: This gecko can only be found on Round Island, near the island of Mauritius, in the south-west Indian Ocean. The volcano on the seabed that formed Round Island, erupted about 100,000 years ago creating a small dome-shaped island about 150 hectares in area.

Threats to Survival: Round Island was once a beautiful island covered with a hardwood forest in the middle and a palm savanna around the edge. Then in 1840, rabbits and goats were released as a possible food supply for future visitors. These introduced animals reproduced rapidly and soon upset the fragile balance of life on the island. They ate all the low growing plants like seedling palms, and other trees and shrubs. The soil was exposed and began to erode. With the soil around their roots washed away, mature trees were easily blown over by occasional cyclones.

Conservation Efforts: In March 1976, Gerald Durrell paid a visit to Round Island to study the situation. It was horrible because the entire hardwood forest was completely gone (except for a single tree). There were scattered palms and large areas of exposed rock everywhere. The Round Island Day Gecko, along with many other local reptiles were all endangered. Durrell spoke with the Mauritian Government and offered to help restore the wildlife on Round Island. They took 16 geckos to the Jersey Zoo for captive breeding, where more than 300 young have been reared. Some have been sent to other zoos including Chester and Bristol (UK); Picton (Canada); Houston and Rio Grande (USA) and Rotterdam (Netherlands). The island habitat itself had to be restored if there would ever be hope of returning the geckos to the wild. First, the rabbits and goats had to be removed allowing the native plants and animals to recover.