The lace monitor or tree goanna (''Varanus varius'') is a member of the

monitor lizard Monitor lizards are lizards in the genus ''Varanus,'' the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are reco ...

family native to eastern Australia. A large lizard, it can reach in total length and in weight. The lace monitor is considered to be a

least-concern species A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

according to the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natur ...

Taxonomy

Lace Monitor - Bell's Form - Fraser Coast

John White, the surgeon-general of New South Wales, described this species as the variegated lizard (''Lacerta varia'') in 1790. George Shaw reported that several specimens were taken back to England. French naturalist François Marie Daudin gave it the name ''Tupinambis variegatus'' in 1802, and noted two forms. German naturalist

Blasius Merrem Blasius Merrem (4 February 1761 – 23 February 1824) was a German naturalist, zoologist, ornithologist, mathematician, and herpetologist. In 1804, he became the professor of political economy and botany at the University of Marburg. Early ...

established the genus '' Varanus'' in 1820, with ''V. varius'' as the first mentioned member set as its

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

John Edward Gray John Edward Gray, Fellow of the Royal Society, FRS (12 February 1800 – 7 March 1875) was a British zoology, zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray ...

in 1827. French zoologists

André Marie Constant Duméril André Marie Constant Duméril (1 January 1774 – 14 August 1860) was a French zoologist. He was professor of anatomy at the Muséum national d'histoire naturelle from 1801 to 1812, when he became professor of herpetology and ichthyology. ...

and

Gabriel Bibron Gabriel Bibron (20 October 1805 – 27 March 1848) was a French zoologist and herpetologist. He was born in Paris. The son of an employee of the Museum national d'histoire naturelle, he had a good foundation in natural history and was h ...

described two specimens in 1836, one in their possession and one from the collection of English zoologist Thomas Bell as ''Varanus bellii'' "Le Varan de Bell". This turned out to be a banded colour phase of the lace monitor that coexists with normal-coloured individuals, and is either autosomal dominant or codominant genetically. It is sometimes called the Bell's phase lace monitor. The lace monitor is

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

; no subspecies are recognised. However, genetic analysis of its mitochondrial DNA (mtDNA) across its range revealed three main clades: a north Queensland clade separated by the

Burdekin Gap The Burdekin Gap, named for the Burdekin River, is a biogeographical feature in Queensland, northeastern Australia, which separates populations of freshwater fishes and other water-dependent land animals, such as the delicate skink (''Lamprophol ...

from a clade spanning from southern Queensland through inland New South Wales across the Murray–Darling basin and into southeastern South Australia. This is divided from a third clade that spans coastal eastern Australia (northern New South Wales to eastern Victoria) by the McPherson Range and Great Dividing Range. This last clade is thought to have diverged from the first two clades around 2.7 million years ago, while these clades separated around 850,000 years ago. Genetic analysis of mtDNA shows the lace monitor to be the closest relative (sister taxon) of the

Komodo dragon The Komodo dragon (''Varanus komodoensis''), also known as the Komodo monitor, is a member of the monitor lizard family Varanidae that is endemic to the Indonesian islands of Komodo, Rinca, Flores, and Gili Motang. It is the largest ext ...

, with their common ancestor diverging from a lineage that gave rise to the crocodile monitor ('' Varanus salvadorii'') of New Guinea. The divergence between lace monitor and Komodo dragon lineages has been calculated to have occurred around 13 million years ago, or 11.5 million years ago. The species is commonly known as lace monitor, tree goanna, or lacy. It was known as ''wirriga'' to the Eora and Darug inhabitants of the Sydney basin, and ''gugaa'' to the Wiradjuri people of southern New South Wales.

Description

The second-largest monitor in Australia after the perentie, the lace monitor can reach 2 m (7 ft) in total length, or 76.5 cm snout–vent length (SVL), and weigh up to 14 kg (30 lb). The male reaches sexual maturity when it has a SVL of 41.5 cm. Females are generally smaller than males, with a maximum SVL of 57.5 cm, and becoming sexually mature at a SVL of 38.5 cm. The tail is long and slender and about 1.5 times the length of the head and body. The tail is cylindrical at its base, but becomes laterally compressed towards the tip. Historically, it has been described as growing as much as 8 ft long. Regardless of the accuracy of these reports, lace monitors of such size likely no longer exist. Argus Monitor and Lace Monitor

Patterning

Lace monitors are found in two forms. The main form is dark grey to dull bluish-black with numerous, scattered, cream-coloured 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, is typically found in west of the Great Dividing Range from Woodgate, Eidsvold, and Mitchell in Queensland to Bourke,

Macksville Macksville is a small town on the Nambucca River in the Nambucca Valley, New South Wales, Australia. It is halfway between Sydney and Brisbane, along the Pacific Highway, approximately 40 minutes north of Kempsey, 40 minutes south of Coffs H ...

and

Port Macquarie Port Macquarie is a coastal town in the local government area of Port Macquarie-Hastings. It is located on the Mid North Coast of New South Wales, Australia, about north of Sydney, and south of Brisbane. The town is located on the Tasman Sea ...

in New South Wales. It has also been reported from Healesville, Rushworth, and Murchison in Victoria and the

Flinders Ranges The Flinders Ranges are the largest mountain range in South Australia, which starts about north of Adelaide. The ranges stretch for over from Port Pirie to Lake Callabonna. The Adnyamathanha people are the Aboriginal group who have inhabit ...

in South Australia. It has a base colour 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.

Distribution and habitat

These common terrestrial and often arboreal monitors are found in eastern Australia and range from Cape Bedford on

Cape York Peninsula Cape York Peninsula is a large peninsula located in Far North Queensland, Australia. It is the largest unspoiled wilderness in northern Australia.Mittermeier, R.E. et al. (2002). Wilderness: Earth’s last wild places. Mexico City: Agrupación ...

to south-eastern

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

. They frequent both open and closed

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

s and forage over long distances (up to a day). The lace monitor is considered to be a

according to the International Union for Conservation of Nature. They 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.

Behaviour

Despite its large size and mass, the lace monitor is an adept climber. One was recorded climbing a brick wall to seek shelter in a thunderstorm. Young lace monitors are even more arboreal than adults. They often spend most of their adult lives in the same area; one individual was recorded living in the same tree for years. A field study in Burragorang, New South Wales found that males over 5 kg ranged over home territories of 65.5 ± 10.0 hectares. They moved around much less in winter.

Reproduction

In at least the temperate regions, the breeding season takes place in the summer. Male lace monitors fight each other by grappling while standing on the hind legs in the breeding season, and up to six males may gather around a receptive female to try and court her. Mating takes several hours. Females lay an average of eight eggs in active termite nests either on the ground or in the trees, although they may lay as many as 12 eggs. 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. These monitors can potentially live to reach over 20 years of age.

Feeding

Lace monitors are predominantly carrion eaters, feeding on already dead carcasses of other wildlife. They consist of

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs ...

s, reptiles, small mammals, birds, with eggs and young birds and mammals making up a larger part of their diet in spring and early summer. Lace monitors 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. A 2012 study in Gippsland found that populations of lace monitors near two rubbish tips were thirty five times greater, with individuals around twice as heavy, as populations in natural forest. The lizards near rubbish tips foraged predominantly on food waste there, with a greater caloric intake. These populations had 5.3 males for each female, compared with 1.9 males per female in natural areas. Despite the apparent increase in population and size, the long-term effect of human impact on the species is unclear. As they often swallow meat whole, they can be at risk of harm from some meat scraps; one was reported with a t-bone steak bone stuck in its throat and another with a plastic fork in its stomach. Another swallowed six golf balls that a chicken owner had placed in their coop to prompt their chickens to lay eggs. They frequently attack the large composting nests of

scrub turkey The Australian brushturkey or Australian brush-turkey or gweela (''Alectura lathami''), also frequently called the scrub turkey or bush turkey, is a common, widespread species of mound-building bird from the family Megapodiidae found in eastern ...

s to steal their eggs, and often show injuries on their tails inflicted by male scrub turkeys pecking at them to drive them away. The species (particularly larger individuals) declined in numbers when the species encountered the advancing cane toad, however lace monitors were abundant in some areas where cane toads had been established for many years. Fieldwork published in 2016 found that larger individuals were less cautious in what they ate, but all lace monitors quickly learned to avoid toads after they had been poisoned.

Predators

Lace monitors are apex predators, though

dingo The dingo (''Canis familiaris'', ''Canis familiaris dingo'', ''Canis dingo'', or '' Canis lupus dingo'') is an ancient (basal) lineage of dog found in Australia. Its taxonomic classification is debated as indicated by the variety of scient ...

packs, wedge-tailed eagles, and

wild boar The wild boar (''Sus scrofa''), also known as the wild swine, common wild pig, Eurasian wild pig, or simply wild pig, is a suid native to much of Eurasia and North Africa, and has been introduced to the Americas and Oceania. The species is ...

s occasionally prey upon them. and like all Australian goannas, they were a favorite traditional food of Australian Aboriginal peoples, and their fat was particularly valued as a medicine and for use in

ceremonies A ceremony (, ) is a unified ritualistic event with a purpose, usually consisting of a number of artistic components, performed on a special occasion. The word may be of Etruscan origin, via the Latin '' caerimonia''. Church and civil (secular ...

Venom

Venom glands in Lace Monitors have been confirmed. The venom is similar to that produced by snakes but not enough to cause serious harm. In late 2005,

University of Melbourne The University of Melbourne is a public research university located in Melbourne, Australia. Founded in 1853, it is Australia's second oldest university and the oldest in Victoria. Its main campus is located in Parkville, an inner suburb n ...

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 Washington State University (Washington State, WSU, or informally Wazzu) is a public land-grant research university with its flagship, and oldest, campus in Pullman, Washington. Founded in 1890, WSU is also one of the oldest land-grant uni ...

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.

Uses

The lace monitor was eaten by the Wiradjuri people; local wisdom advised eating lace monitors as they came down from trees as those that had eaten on the ground tasted of rotting meat. The Tharawal ate the species' eggs, collecting them in sand on riverbanks in the Nattai and Wollondilly. Goanna remains have been recovered in middens in what is now Sydney. The lace monitor is bred in captivity as an

exotic pet An exotic pet is a pet which is relatively rare or unusual to keep, or is generally thought of as a wild species rather than as a domesticated pet. The definition varies by culture, location, and over time—as animals become firmly enough est ...

Gallery

File:Varanus varius -Airlie Beach, Queensland, Australia -molting-8.jpg, Molting in Queensland File:Goanna coming down a tree in our garden.jpg, Goanna coming down a tree outside Cooktown, Queensland File:Goana lace monitor.jpg, Climbing a tree File:Goana444.jpg, Climbing a tree File:Wild Lace Monitor in Brisbane Forest Park.jpg, Wild lace monitor in Brisbane Forest Park, Queensland File:Lace monitor (goanna).jpg, Variety: Common form of patterning, Cairns, Queensland File:Lace monitor444.jpg, ''Varanus varius'' prowling demonstrating camouflage File:Varanus varius1.jpg, Lace monitor climbing a tree File:Lace Monitors.jpg, Lace monitors fighting File:Lace Monitor (Glenrock State Conservation Area).jpg, Lace monitor (Glenrock State Conservation Area), Newcastle, New South Wales File:Lace Monitor at The Pass, Byron Bay.jpg, Lace monitor at the pass, Byron Bay, New South Wales File:Varanus varius (12209494164).jpg, Head closeup File:Lace Monitor at Peacock - Richmond Range National Park.jpg, Lace Monitor at Peacock - Richmond Range National Park File:Goannayeramba.jpg, Yeramba Lagoon File:Large Lace Monitor climbing a tree.jpg, Lace monitor climbing a tree, Middle Harbour - Seaforth NSW