Hypnale nepa
SUBFAMILY
Crotalinae
TAXONOMY
Hypnale nepa Laurenti, 1768, Sri Lanka. No subspecies are recognized.
OTHER COMMON NAMES
None known.
PHYSICAL CHARACTERISTICS
The Sri Lankan hump-nosed pitviper is a small snake. Adults usually are 11.8–13.8 in (300–350 mm) in total length, but slightly larger specimens are known. The ground color of the dorsum is light or dark brown with 17–26 pairs of small dark brown blotches. In some individuals, the thin, dark postocular stripe is bordered dorsally by a thin white line. The snout is upturned and bears a small hump covered by tiny scales. As in other members of the genus, the five posterior head plates are mainly intact, but the anterior plates (internasals and prefrontals) are replaced by numerous small scales. Seven to nine supralabial, 124–142 ventral, 33–41 subcaudal, and 17 midbody scale rows have been recorded for this species.
DISTRIBUTION
The species occurs in southwestern Sri Lanka.
HABITAT
Their habitat is wet forest from near sea level to 6,000 ft (1,830 m). Additional study is needed to assess the lower elevation limits of this species; it is possible that specimens of Hypnale nepa and H. walli have been confused in some reports.
BEHAVIOR
The Sri Lankan hump-nosed pitviper is terrestrial and mainly nocturnal, but it sometimes is encountered during the day. It is not aggressive and generally does not attempt to bite unless it is molested.
FEEDING ECOLOGY AND DIET
Known prey include lizards, snakes, frogs, and reptile eggs.
REPRODUCTIVE BIOLOGY
Little is known about the reproduction of this species. It gives birth to live young. Gravid females containing four to six immature eggs have been reported.
CONSERVATION STATUS
This species is not listed by the IUCN. However, with its limited distribution and preference for areas of dense forest, the Sri Lankan hump-nosed pitviper is vulnerable to habitat destruction. Fortunately, there are national parks and forest reserves within its range.
SIGNIFICANCE TO HUMANS
This is a dangerously venomous snake, but reports of contact with humans are few.
