The white snake of the Selangor caves
A brief note by H.N. Ridley describing the cave-adapted coloration of Coluber tæniurus, a white snake newly recorded from the Selangor caves near Kuala Lumpur.
Summary
The article reports that specimens captured by Ridley and C. B. Harvey in December 1896 were identified by G. A. Boulenger at the Natural History Museum as C. tæniurus, a species previously known from Darjeeling, Sumatra, Borneo, and China but not the Malay Peninsula. Ridley provides a detailed colour description of the Selangor population—bluish-grey head, pale ocreous back with isabelline-tipped scales, yellowish vertebral centre, pale yellowish-white belly, and a white-and-black barred tail—and notes that all ten specimens examined were uniform in colour (pp. 99–100).
He argues that the snake’s coloration is a remarkable adaptation to the pale ocreous-yellow limestone walls of the caves, where it rests motionless on ledges near bat roosts to ambush its prey, making it nearly invisible against the rock but conspicuous on the dark cave floor. Comparing his specimens with Boulenger’s catalogue description, Ridley highlights significant colour differences (the catalogue describes a much darker olive-grey-brown animal with black transverse lines) and concludes that the cave form is “at least on the way to become a species distinct in the eyes even of the systematist” (pp. 100–101).