page_title: Mangrove monitor
section_title: Anatomy and morphology
hierarchical_section_title: Mangrove monitor / Anatomy and morphology
caption_attribution_description: English: Varanus indicus from Guam monitor lizard
context_page_description: The mangrove monitor, mangrove goanna, or Western Pacific monitor lizard is a member of the monitor lizard family with a large distribution from northern Australia and New Guinea to the Moluccas and Solomon Islands. Populations from the Marshall Islands, Caroline Islands, and Mariana Islands formerly classified in V. indicus are now considered to comprised two distinct species. It grows to lengths of 3.5 to 4 ft.
context_section_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. 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 gives a total length of 100 cm for Australian specimens. 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 and dropping the lower jaw to eat large prey, a process similar in appearance to that of snakes, although the jaw of the mangrove monitor remains rigid. The mangrove monitor possesses a Jacobson's organ, 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.
caption: juvenile
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