Varanus indicus species-complex

Varanus indicus species-complex

Black-backed Mangrove Monitor (Varanus yuwonoi)

This distinctive species was described in 1998 (Harvey & Barker). They are the largest of the indicus-complex species with captive individuals known to reach six feet. Unsubstantiated reports exist of specimens as large as seven feet.

Varanus yuwonoi is known mainly from mountainous forests up to 300 meters in elevation. They are found in close proximity to streams during the dry season and move further up in elevation during the wet. While often encountered on the ground, this species climbs well and is believed to be semi-arboreal. This species is said to be difficult to find in the wild and is believed to be an ambush predator (Weijola 2010).

Distinctive Features (from Harvey & Barker 1998)

Background color: Anterior third black; posterior two-thirds olive

Dorsal pattern: Anterior third solid black, though in younger animals black areas appear as transverse bands; posterior third covered in numerous dark flecks

Tail pattern: Anterior third flecked as on the dorsum; posterior two-thirds banded (blue pigmentation present)

Throat/ventral pattern: Ventral surface light yellowish; throat may be faintly blotched

Post-ocular stripe: Present

Tongue color: Purple with a yellowish tip


Known from the Jailolo District of northern Halmahera in the Moluccas, though locals suggest it may occur throughout the island. Records from Morotai, Bacan, and Obi exist but need to be verified (Weijola 2010).

Juvenile. Photos courtesy of Joey Mugleston.

Photos courtesy of Joey Mugleston. (Note: These are the same specimens shown as juveniles above, showing considerable dulling of color with age)

Captive-bred hatchling; photo courtesy of Ben Siegel.

 Photo courtesy of Robert Sprackland.

Status in Captivity

Varanus yuwonoi has been kept in the pet trade. They have been successfully reproduced though the majority of specimens are still wild-caught. Due to its large size and high cost (unusual for indicus-complex animals... specimens typically sell for at least four figures), this species remains rather uncommon.


Harvey, M. B. & D. G. Barker (1998): A new species of blue-tailed monitor lizard (genus Varanus) from Halmahera island, Indonesia. Herpetologica 54: 34-44.

Weijola, V. S. A. (2010): Geographical distribution and habitat use of monitor lizards of the north Moluccas. Biawak 4 (1): 7-23. (