Varanus Indicus
   HOME

TheInfoList



OR:

The mangrove monitor, mangrove goanna, or Western Pacific monitor lizard (''Varanus indicus'') 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 West African Nile monitor, one species is also found in south America as an invasive species. A ...
family with a large distribution from northern
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
and
New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...
to the
Moluccas The Maluku Islands ( ; , ) or the Moluccas ( ; ) are an archipelago in the eastern part of Indonesia. Tectonically they are located on the Halmahera Plate within the Molucca Sea Collision Zone. Geographically they are located in West Melanesi ...
and
Solomon Islands Solomon Islands, also known simply as the Solomons,John Prados, ''Islands of Destiny'', Dutton Caliber, 2012, p,20 and passim is an island country consisting of six major islands and over 1000 smaller islands in Melanesia, part of Oceania, t ...
. It grows to lengths of . It is also known as wbl yb in the
Kalam language Kalam is a Kalam language of Papua New Guinea. It is closely related to Kobon, and shares many of the features of that language. Kalam is spoken in Middle Ramu District of Madang Province and in Mount Hagen District of Western Highlands Prov ...
of
Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...
.


Taxonomy

The mangrove monitor was first described by the French
herpetologist Herpetology (from Ancient Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is a branch of zoology concerned with the study of amphibians (including frogs, salamanders, and caecilians (Gymnophiona)) and reptiles (in ...
François Marie Daudin François Marie Daudin (; 29 August 1776 in Paris – 30 November 1803 in Paris) was a French zoologist. Biography With legs paralyzed by childhood disease, he studied physics and natural history but ended up being devoted to the latter. Daudin w ...
in 1802. Daudin's original
holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
of a subadult specimen was collected on Ambon, Indonesia, and has since disappeared from the museum in
Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...
. Daudin's original name for the species was ''Tupinambis indicus'', an appellation it would carry for 100 years until being renamed as a ''Varanus''. The
generic Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...
name ''Varanus'' is derived from the
Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...
word ''waral'' (ورل), which translates to English as "monitor". Its
specific Specific may refer to: * Specificity (disambiguation) * Specific, a cure or therapy for a specific illness Law * Specific deterrence, focussed on an individual * Specific finding, intermediate verdict used by a jury in determining the final ...
name, ''indicus'', is
Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
for the country of
India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
, but in this instance it relates to
Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
or the
East Indies The East Indies (or simply the Indies) is a term used in historical narratives of the Age of Discovery. The ''Indies'' broadly referred to various lands in Eastern world, the East or the Eastern Hemisphere, particularly the islands and mainl ...
, where the animal was first described. Due to its large geographic
range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...
, ''V. indicus'' is considered a
cryptic species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...
of at least four species: ''Varanus indicus'', '' Varanus doreanus'', '' Varanus spinulosus'', and '' Varanus jobiensis''. More research is being done on possible future species within this complex, not surprisingly, since it has had over 25 different scientific names since it was first described. Populations from
Guam Guam ( ; ) is an island that is an Territories of the United States, organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, Guam, Hagåtña, and the most ...
, the
Marshall Islands The Marshall Islands, officially the Republic of the Marshall Islands, is an island country west of the International Date Line and north of the equator in the Micronesia region of the Northwestern Pacific Ocean. The territory consists of 29 c ...
,
Caroline Islands The Caroline Islands (or the Carolines) are a widely scattered archipelago of tiny islands in the western Pacific Ocean, to the north of New Guinea. Politically, they are divided between the Federated States of Micronesia (FSM) in the cen ...
and
Mariana Islands The Mariana Islands ( ; ), also simply the Marianas, are a crescent-shaped archipelago comprising the summits of fifteen longitudinally oriented, mostly dormant volcanic mountains in the northwestern Pacific Ocean, between the 12th and 21st pa ...
formerly classified in ''V. indicus'' are now considered to comprise two distinct species:
Bennett's long-tailed monitor Bennett's long-tailed monitor (''Varanus bennetti'') is a species of monitor lizard in the family Varanidae. It is found in Palau, the Federated States of Micronesia, and the Northern Mariana Islands. Etymology The specific epithet, ''bennett ...
(''V. bennetti'') and the
Mariana monitor ''Varanus tsukamotoi'', the Mariana monitor or Saipan monitor, is a species of lizard of the family (biology), family Varanidae. It is Endemism, endemic to the Northern Mariana Islands and Guam, and has been introduced to Japan in the Marshall Is ...
(''V. tsukamotoi'').


Distribution and habitat

The mangrove monitor's range extends throughout northern Australia, New Guinea, and the Solomon Islands, where it inhabits damp forests near coastal rivers, mangroves, and permanent inland lakes. It also occurs on the
Moluccan Moluccans are the Melanesian-Austronesian and Papuan-speaking ethnic groups indigenous to the Maluku Islands (also called the Moluccas). The region was historically known as the Spice Islands, and today consists of two Indonesian provinces of ...
islands of Morotai,
Ternate Ternate (), also known as the City of Ternate (; ), is the List of regencies and cities of Indonesia, city with the largest population in the province of North Maluku and an island in the Maluku Islands, Indonesia. It was the ''de facto'' provi ...
,
Halmahera Halmahera, formerly known as Jilolo, Gilolo, or Jailolo, is the largest island in the Maluku Islands. It is part of the North Maluku Provinces of Indonesia, province of Indonesia, and Sofifi, the capital of the province, is located on the west coa ...
, Obi,
Buru Buru (formerly spelled Boeroe, Boro, or Bouru) is the third largest island within the Maluku Islands of Indonesia. It lies between the Banda Sea to the south and Seram Sea to the north, west of Ambon Island, Ambon and Seram Island, Seram island ...
, Ambon,
Haruku Haruku Island is an island in Central Maluku Regency, Maluku Province, Indonesia - lying east of Ambon Island, off the southern coast of Seram and just west of Saparua. It is administered as a single district, Haruku Island District (''Kecamatan ...
, and
Seram Seram (formerly spelled Ceram; also Seran or Serang) is the largest and main island of Maluku province of Indonesia, despite Ambon Island's historical importance. It is located just north of the smaller Ambon Island and a few other adjacent i ...
in Indonesia. Within this range of thousands of miles across hundreds of islands are large variations in size, pattern, and scalation. The monitors have also been introduced to
Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...
since the 1940s.


Description

The monitor's body is dark green or black in color and covered with golden-yellow spots, with light coloration on the top of its head and a solid, cream-colored belly lacking dark markings. It has a distinct dark purple tongue and serrated teeth.Bennett, D. (1995). ''A Little Book of Monitor Lizards''.
Aberdeen Aberdeen ( ; ; ) is a port city in North East Scotland, and is the List of towns and cities in Scotland by population, third most populous Cities of Scotland, Scottish city. Historically, Aberdeen was within the historic county of Aberdeensh ...
, U.K.:Viper Press.
The mangrove monitor attains different sizes in different parts of its range, but seldom if ever exceeds 1.3 m in total length. Australian herpetologist
Harold Cogger Harold George "Hal" Cogger (born 4 May 1935) is an Australian herpetologist. He was curator of reptiles and amphibians at the Australian Museum from 1960 to 1975, and Deputy Director of the museum from 1976 to 1995. He has written extensively on A ...
gives a total length of 100 cm for Australian specimens. Cogger, H. (1967). ''Australian Reptiles in Colour''. Sydney: A.H. & A.W. Reed, The tail is almost twice the length of the body and laterally compressed to aid in swimming. Like the rest of the lizard's body, it is covered with small, oval, keeled scales. This monitor has the ability to increase the size of its mouth by spreading the
hyoid apparatus The hyoid apparatus is the collective term used in veterinary anatomy for the bones which suspend the tongue and larynx. It consists of pairs of stylohyoid, thyrohyoid, epihyoid and ceratohyoid bones, and a single basihyoid bone. The hyoid appar ...
and dropping the lower jaw to eat large
prey Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not ki ...
, a process similar in appearance to that of
snakes Snakes are elongated Limbless vertebrate, limbless reptiles of the suborder Serpentes (). Cladistically Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales much like other members of ...
, although the jaw of the mangrove monitor remains rigid.King, Dennis & Green, Brian (1999). ''Goannas: The Biology of Varanid Lizards''. University of New South Wales Press. . The mangrove monitor possesses a
Jacobson's organ The vomeronasal organ (VNO), or Jacobson's organ, is the paired auxiliary olfactory (smell) sense organ located in the soft tissue of the nasal septum, in the nasal cavity just above the roof of the mouth (the hard palate) in various tetrapods. T ...
, which it uses to detect prey, sticking its tongue out to gather scents and touching it to the opening of the organ when the tongue is retracted. The mangrove monitor is one of only two species of monitor lizards that possess salt-excreting nasal glands, the other being '' V. semiremex,'' which enables them to survive in saltwater conditions and to consume marine prey. The presence of this gland probably enabled the monitors to reach new islands and aid in its dispersal throughout the Pacific.


Diet

The mangrove monitor is an opportunistic
carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they ar ...
, feeding on the eggs of reptiles and birds, mollusks, rodents, insects, crabs, smaller lizards, fish, and carrion. Mangrove monitors are the only monitor capable of catching fish in deep water.Traeholt, C. (1993). "Notes on the feeding behaviour of the water monitor, ''Varanus salvator''." ''Malay. Nat. J.'' 46: 229-241. In some parts of its range, it is known to eat juvenile
crocodile Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large, semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term "crocodile" is sometimes used more loosely to include ...
s.


Reproduction

Males fight for females, and in one observation, after mounting the female, the male used his chin to rub the dorsum of the female's head and forequarters. While mounted and oriented head to head, the male and female slowly rotated in a clockwise direction through 360°, with the male remaining superior. Female mangrove monitors lay two to 12 eggs that measure 3.5 to 5 cm in length. The oblong eggs are white, and hatch in about seven to eight months.Bennett, Daniel (1998). ''Monitor lizards: Natural history, biology & husbandry''. Edition Chimaira. . The first successful captive breeding of this species was at the
Philadelphia Zoo The Philadelphia Zoo is a zoo located in the Centennial District of Philadelphia on the west bank of the Schuylkill River. It was the first true zoo in the United States; it was chartered by the Commonwealth of Pennsylvania on March 21, 1859 ...
in 1993. The Reptilian Zoo in Vlissingen, the Netherlands, was reported to have successfully hatched eggs by a female animal which was not in any contact with a male of the same species.


Contact with humans

Humans have introduced the mangrove monitor to a number of Pacific Islands since the 1930s. They have been present on Ifaluk in the western Caroline Islands since the
Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
.Uchida, T. (1967). Observations on the monitor lizard, ''Varanus indicus'' (Daudin) as a rat control agent on Ifaluk, Western Caroline Islands. ''Micronesica'' 3(1):17-18 The Japanese introduced the lizards to the Marshall Islands prior to World War II to eliminate rats; the lizards flourished and soon began to raid the local chicken houses.Dryden, G. (1965). The food and feeding habits of ''Varanus indicus'' on Guam. ''Micronesica'' 2(1):73-76. When American troops arrived, the locals asked them for help in getting rid of the mangrove monitors. The US response was to introduce the
cane toad The cane toad (''Rhinella marina''), also known as the giant neotropical toad or marine toad, is a large, Terrestrial animal, terrestrial true toad native to South America, South and mainland Central America, but which has been Introduced spe ...
(''Rhinella marina'') which proved toxic to the lizards. As the monitor population dropped, however, the rat population began to rise. The mangrove monitor is hunted in many places for its skin, which is used for leather in making drum heads. Although international trade in this species is small, Mertens referred to it as one of the most heavily exploited monitor lizards. Sprackland, R. G. (1993). Rediscovery of a Solomon Islands monitor lizard (''Varanus indicus spinulous'') Mertens, 1941. ''Vivarium'' 4(5):25-27. In 1980, trade in over 13,000 monitors was declared. However, in many remote places, they are used as a food source and are killed because of their reputation for
prey Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not ki ...
ing on domestic animals. Mangrove monitors are often kept in
zoo A zoo (short for zoological garden; also called an animal park or menagerie) is a facility where animals are kept within enclosures for public exhibition and often bred for conservation purposes. The term ''zoological garden'' refers to zoology, ...
s and private collections, as they are an active and alert, and generally can be handled if tamed properly. Most specimens defecate on their handlers when stressed. With proper care they can live up to 20 years in captivity.Sprackland, Robert (1992). ''Giant Lizards''. TFH Publications. .


References

{{Taxonbar, from=Q1446363 Varanus Reptiles of the Solomon Islands Reptiles described in 1802 Monitor lizards of Australia Marine reptiles Taxa named by François Marie Daudin