Goanna is the umbrella name given to the group of large Australian lizards in the monitor family. Monitors are large lizards native to Australia, Africa and throughout Asia. They are known for their size, strong tails, sharp claws and long forked tongues which are used to taste the air around them. Perhaps the best known, and largest monitor lizard is the Komodo dragon. This species can reach lengths of up to 3 meters and weigh up to 90 kilograms and have quite a fearsome reputation. Here in Australia our monitor lizards don’t quite reach the massive size of the Komodo dragon however some species can still grow to quite formidable sizes of up to 2 meters. The lace monitor also known, a species native to eastern Australia is the most common species that can be spotted around the Whitsundays both on the mainland and on the islands.
The lace monitor is the second largest monitor species in Australia after the perentie and when fully grown can reach lengths of 2 meters but are more commonly seen at lengths of 1-1.5 meters and sometimes weighing up to 14 kilograms. The most common colouring of this species is a dark grey to black base with cream/yellow spots or banding, they are also lighter in colour on the belly. The banding is more prominent in juveniles and fades and becomes less distinct as they age. Like all monitor species these guys also have very well developed and muscled legs. These strong legs mean that they are excellent runners which can reach high speeds over long distances. The ability to maintain high speeds over long distances can be attributed to specialised muscles in the goannas neck. These muscles allow the animals to actively pump air into their lungs while separate muscles work in the action of running preventing them from becoming “puffed out”. The large claws of all goanna species are also another notable feature. These claws are perfect for climbing and as a result the lace monitor will spend a large amount of its time in trees, earning it another name, the tree goanna.
Due to the amount of time they spend in trees the lace goanna finds a lot of its food high up in the treetops. They will catch unsuspecting birds and even raid the birds nests for eggs. They will also feed on insects, other reptiles, mammals and even carrion. They are also quite opportunistic feeders and if an easy meal presents itself they will take it. This means that they have no qualms about helping themselves into chicken coops, camp sites and houses. Those lizards which live in close proximity to humans and are at ease around them will even approach people with food in the hopes that they will get thrown a scrap or two.
Being reptiles the goannas are what is known as cold blooded, or ectothermic. This means that they are unable to produce their own body heat like mammals and instead must use their environment to regulate their body temperature. Due to this they are most active during the day when the sun is up. To warm their bodies after the cool night they will often sit out on a rock or tree branch in the sun to absorb as much heat as possible. Once they are sufficiently warmed up they are able to be much more active and will fo about their day foraging for food. They will also breed in the warmer summer months and become inactive during winter.
Breeding season can be quite an aggressive time for the goannas. Females will often be surrounded by up to six males. These males will fight each other while standing on their hind legs and grappling with each other, the winner earns the right to mate with the female. Female lace monitors will lay between 6-12 eggs in a nest which is quite often a hole in the ground filled with leaf litter and grass. After 8-10 weeks the eggs will hatch and the female will return to her nest to dig them out. Once they have left the nest there is no parental care and the baby lace monitors must fend for themselves.
The goannas in Australia are part of an ancient lineage and have a significant place in Australian indigenous history and culture. They have long been an important traditional food source and are a prominent feature in many Aboriginal dreamtime stories. These beautiful ancient lizards can be seen quite regularly on the many bush walks on the islands, they are even a common character seen around the picnic areas on south Whitehaven showing no fear of the humans who frequent the beach. However even though the goannas are at ease in our presence it is still important to give them their space and not approach them or attempt to feed them as they can become aggressive towards humans if they feel threatened and inflict nasty wounds with their sharp claws and feet.