The black-headed ground snake is a small, burrowing snake with a slender body reaching just in total length (body + tail). Its smooth and shiny
dorsal scales and almost transparent covering make many of its internal organs quite visible, when observed against a light source. The eyes are small, with black irises. The head is covered with symmetrical large shields. The
rostral shield is somewhat enlarged and specialized for digging through soil. The
dorsal coloration may vary from tan to orange, with no obvious pattern except on the neck and head. The belly is clear white. The pattern on the neck and head is different in the two subspecies. In the
nominate subspecies,
Rhynchocalamus melanocephalus melanocephalus, there is no separation between the neck pattern and the head pattern. The upper surface of the head and neck is ash-black. Only the
labials, the
nasals, and the rostal are white. In
R. melanocephalus satunini the neck carries a black semi-collar, and the head pattern consists of three transverse black saddles. The first one is on the rostral. The second spreads over the postnasal, supraorbital, and
frontal, and partially over the
prefrontal shields from eye to eye. The third saddle covers the
parietal shields and some of the surrounding scales. The spaces between the black saddles are white, which makes
Rhynchocalamus visually identifiable from similar looking species of the
genera Eirenis and
Pseudocyclophis, which often occupy the same
habitat. ==Natural history==