Lace Monitor

## Description

The lace monitor or tree goanna (Varanus varius ) is a member of the monitor lizard family native to eastern Australia. A large lizard, it can reach 2 metres (6.6 ft) in total length and 14 kilograms (31 lb) in weight. The lace monitor is considered to be a least-concern species according to the International Union for Conservation of Nature.

## Appearance

Lace monitors are large lizards native to eastern Australia. They are found in two forms. The main form is dark grey to dull bluish-black with numerous, scattered, cream-colored spots. The head is black and the snout is marked with prominent black and yellow bands extending under the chin and neck. The tail has narrow black and cream bands, which are narrow and get wider towards the end of the tail. Juveniles have more defined and prominent banding, with five narrow black bands on the neck and eight bands on the body. The other type, known as Bell's form, has a base color of yellow-brown or yellow with fine black mottling and broad, black or dark brown bands from the shoulders to the tail. The top of the head is black. Female Lace monitors are generally smaller than males.

## Distribution

Lace monitors are found in eastern Australia and range from Cape Bedford on the Cape York Peninsula to south-eastern South Australia. They inhabit both dry tropical forests and cool temperate forests.

## Behavior

Lace monitors are terrestrial and often arboreal reptiles. Despite their large size and mass, they are adept climbers. Lace monitors are generally solitary and diurnal lizards. They search for food on the ground, retreating to a nearby tree if disturbed. They also forage in areas inhabited by people, raiding chicken coops for poultry and eggs, and rummaging through unprotected domestic garbage bags and rubbish bins in picnic and recreational areas. Lace monitors are mainly active from September to May but are inactive in cooler weather and shelter in tree hollows or under fallen trees or large rocks.

## Venom

In late 2005, University of Melbourne researchers discovered that all monitors may be somewhat venomous. Previously, bites inflicted by monitors were thought to be prone to infection because of bacteria in their mouths, but the researchers showed that the immediate effects were more likely caused by envenomation. Bites on the hand by lace monitors have been observed to cause swelling within minutes, localised disruption of blood clotting, and shooting pain up to the elbow, which can often last for several hours. In vitro testing showed lace monitor mouth secretion impact on platelet aggregation, drop blood pressure and relax smooth muscle; the last effect mediated by an agent with the same activity as brain natriuretic peptide. Liquid chromatography/mass spectrometry found ample proteins with molecular masses of 2-4 kilodaltons (corresponding with natriuretic peptide), 15 kilodaltons (type III Phospholipase A2), and 23-25 kilodaltons (cysteine-rich secretory proteins and kallikrein) in these secretions. Washington State University biologist Kenneth V. Kardong and toxicologists Scott A. Weinstein and Tamara L. Smith, have cautioned that labelling these species as venomous oversimplifies the diversity of oral secretions in reptiles, and overestimates the medical risk of bite victims.

## Diet

Lace monitors are carnivores and scavengers. They feed on insects, reptiles, small mammals, birds, and birds' eggs. They are also carrion eaters, feeding on already dead carcasses of other animals.

## Reproduction

In the temperate regions, the breeding season of Lace monitors takes place in the summer. During this time males fight each other for their right to mate with the females; they will struggle while standing on the hind legs and intimidate each other with their inflated throat pouch. Females lay 8-12 eggs in active termite nests either on the ground or in the trees. When such nests are in short supply, females often fight over them or lay the eggs in burrows and perhaps hollow logs. The eggs overwinter to hatch 6-7 months later. Hatchlings remain around the nest for about a week or more before leaving its vicinity. Females may return to the same termite nest to lay their next clutch of eggs. Young Lace monitors typically reach reproductive maturity when they are 4-5 years old.

## Population

### Population threats

The Lace monitor doesn't face serious threats at present. However, continuous loss of their habitat can lead to a serious threat to this species in the future.

### Population number

According to IUCN, the Lace monitor is locally common throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.

## Fun Facts for Kids

The Lace monitor is the second-largest monitor in Australia.

The Lace monitor is also commonly known as tree goanna, or lacy. The Eora and Darug inhabitants of the Sydney basin knew it as 'wirriga', and the Wiradjuri people of southern New South Wales called it 'gugaa'.

The Lace monitor is mildly venomous.

In order to find food, Lace monitors may cover up to 3 km (1.9 mi) in one day.

Lace monitors are so excellent climbers that one individual was even seen climbing a brick wall to seek shelter in a thunderstorm. Young Lace monitors are even more arboreal than adults.

Lace monitors often spend most of their adult lives in the same area and it was recorded that one monitor was living in the same tree for years.

Lace monitors frequently attack the large composting nests of scrub turkeys to steal their eggs and therefore often have injuries on their tails. These injuries are inflicted by male scrub turkeys who peck at the tails of monitors to drive them away.