How to Identify Chasen's Mountain Pit Viper (Identification Guide)
A guide to recognizing Chasen's Mountain Pit Viper by its stout brownish body, triangular head, heat-sensing pits, and high-elevation Bornean range.
Read the full Chasen's Mountain Pit Viper encyclopedia entry →Key identifying features
Chasen's Mountain Pit Viper (Ovophis chaseni) is a venomous pit viper found in the mountainous regions of Borneo, identifiable by its stout body, broad triangular head, heat-sensing facial pits, and rough keeled scalation typical of pit vipers, combined with a more terrestrial, ground-dwelling habit than many green arboreal relatives.
Coloration & pattern
The body is typically brown, reddish-brown, or grayish-brown, marked with darker brown or blackish crossbands or blotches that provide effective camouflage among leaf litter and forest floor debris. This mottled brown pattern contrasts with the more uniformly green coloration seen in many related arboreal pit vipers.
Head, eyes & scales
The head is broad, triangular, and clearly distinct from the neck, with a heat-sensing pit between the eye and nostril on each side used to detect warm-blooded prey. Eyes have vertically elliptical pupils typical of pit vipers. The scales are heavily keeled, giving the skin a rough, textured feel suited to a life spent largely on the forest floor.
Size & body shape
This is a small to medium, relatively stout-bodied pit viper, generally reaching 40–70 cm (16–28 inches), with a build more suited to terrestrial movement through leaf litter than active climbing.
Range & habitat where you'll see it
Chasen's Mountain Pit Viper is found in montane forests of Borneo, typically at moderate to high elevations, favoring cool, moist forest floor habitats with abundant leaf litter. Unlike many pit vipers that are highly arboreal, this species is more frequently encountered on or near the ground.
How to tell it apart from look-alikes
Its brown, mottled, leaf-litter-camouflaging pattern distinguishes it from the more commonly green, arboreal pit vipers found in the same general region, such as various Trimeresurus and Parias species. Its more terrestrial habits and stouter build compared to slender arboreal pit vipers also aid identification, along with its montane Bornean range. As with all pit vipers, the triangular head, heat-sensing pits, and vertical pupils separate it from non-venomous ground snakes with superficially similar brown, blotched patterns.
Frequently asked questions
Is Chasen's Mountain Pit Viper venomous?
Yes, it is a venomous pit viper found in Borneo's montane forests.
Is this species mostly found in trees or on the ground?
It is more terrestrial than many related pit vipers, typically found on or near the forest floor among leaf litter.
What color is Chasen's Mountain Pit Viper?
It is generally brown, reddish-brown, or grayish-brown with darker mottled crossbands, unlike the green coloration of many related species.
Where is this species found?
It occurs in montane forests of Borneo, typically at moderate to high elevations.
How can I tell it apart from a non-venomous ground snake?
Look for the broad triangular head, heat-sensing facial pits, and vertical pupils characteristic of pit vipers, which non-venomous species lack.