Spineless forest lizard (Calotes liocephalus)

Spineless forest lizard
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Spineless forest lizard fact file

Spineless forest lizard description

GenusCalotes (1)

The spineless forest lizard is one of four Calotes species endemic to Sri Lanka, which all share a common set of characteristics (2). These include a relatively short head, with swollen cheeks, backwards, or backwards and downwards pointing scales on the side of the body, and a tail that is strongly swollen at the base in fully grown adult males (2). This lizard is patterned with a mixture of pale moss-green, dark green and brown indistinct stripes on its body, extending from the back down the sides to the belly, and pale moss-green and dark brown to black rings around its limbs and tail. This cryptic colouration helps camouflage the small lizard from potential predators in the treetops of its habitat. The spineless forest lizard closely resembles the green garden lizard (Calotes calotes) but can be distinguished by the absence of spines above the ear found in other Calotes species (3), a feature that has earned the lizard its common name.

Also known as
crestless lizard.
Male length (excluding tail): 89 mm (2)
Female length (excluding tail): 83 - 90.5 mm (2)

Spineless forest lizard biology

Few studies of the spineless forest lizard have taken place and little is therefore known of its biology. Unlike most lizards belonging to the Agamidae family, this species spends most of its time in the trees, rather than on the ground (6) (7). Agamids are diurnal and visually-orientated, with the crests and other ornamentation thought to serve as important signals in establishing and maintaining territories or in courtship (6) (8). Most agamids feed on insects and other small animals, although a few also feed on plant matter as adults (8). Like the vast majority of agamids, the spineless forest lizard is oviparous, or egg-laying (6).


Spineless forest lizard range

This species is confined to the Knuckles Mountains, Agra-Bopath and Peak Wilderness regions of Sri Lanka, where it is found from 800 – 1,900 m above sea level (3) (4). Of the three protected areas listed above, the lizard is much more prominent in the Knuckles Mountains (5).


Spineless forest lizard habitat


Spineless forest lizard status

Classified as Endangered (EN) on the IUCN Red List 2006 (1).

IUCN Red List species status – Endangered


Spineless forest lizard threats

Habitat destruction, fragmentation and disturbance pose a serious threat to the spineless forest lizard, with Sri Lanka’s forests having been dramatically reduced in recent years due to clearance of montane forest mainly for cardamom cultivation, but also for grazing livestock, by logging companies, illegal logging and removal of timber by peripheral villagers (5) (7). Indeed, much of the forest understorey has been cleared for planting cardamom in the Knuckles Mountains where this lizard is found, although the canopy has been retained for shade (4). The Agra-Bopath area of this species’ range is becoming increasingly isolated by surrounding vegetable cultivations and tea plantations, with the lack of clearly demarcated boundaries leading to significant encroachment into this forest (4) (5). Isolation of populations prevents both important genetic flow between subpopulations and means of escape from forest fires (4) (7). Further more, there is intensive use of pesticides on vegetable cultivations and tea plantations in Sri Lanka, which could be having a serious polluting affect. Although the impact these chemicals are having on non-target species is not yet known, studies elsewhere indicate that they could potentially be devastating (4), with possibilities for bioaccumulation (5). Climatic change and global warming may also be having a negative impact on the species as a result of forest diebacks due to acid rain (5). Domestic animals in the Knuckles Mountains such as cats, dogs and poultry also prey on reptiles (7), although the arboreal nature of the spineless forest lizard probably limits this threat.


Spineless forest lizard conservation

Project Knuckles 2004 was initiated to conduct the first in-depth study of reptiles and the primary threats facing them in the Knuckles Mountain Range (7). It was discovered that the region held some of the highest reptile diversity in the country, and is therefore an important site for conservation (9). The spineless forest lizard was one of three target species studied (9). The mountain range currently has little protected status or conservation management, but the discovery of many endemic and endangered reptiles in the area may help campaigns to achieve greater protection in the future (4).

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more

For more information on conservation in Sri Lanka, see:



Authenticated (06/11/2006) by Thilina Surasinghe, Department of Zoology, University of Sri Jayewardenepura , Sri Lanka.



Living in trees.
The process by which the concentrations of some toxic chemicals gradually increase in living organisms as they breathe contaminated air, drink contaminated water, or eat contaminated food.
Active during the day.
A species or taxonomic group that is only found in one particular country or geographic area.


  1. IUCN Red List (January, 2006)
  2. Bahir, M.M. and Maduwage, K.P. (2005) Calotes Desilvai, A New Species of Agamid Lizard from Morningside Forest, Sri Lanka. The Raffles Bulletin of Zoology, 12: 381 - 392. Available at:
  3. SriLankaReptile.com (May, 2006)
  4. Bahir, M.M. and Surasinghe, T.D. (2005) A Conservation Assessment of Sri Lankan Agamidae (Reptilia: Sauria). The Raffles Bulletin of Zoology, 12: 407 - 412. Available at:
  5. Surasinghe, T. (2006) Pers. comm.
  6. Animal Diversity Web (May, 2006)
  7. Project Knuckles (May, 2006)
  8. Laboratory for Functional Morphology (May, 2006)
  9. The University of Edinburgh: Expeditions Committee (May, 2006)

Image credit

Spineless forest lizard  
Spineless forest lizard

© Chris Mattison / www.photoshot.com

NHPA/Photoshot Holdings Ltd
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