Lycodon Bicolor

Lycodon bicolor, also historically referred to as Lycodon mackinnoni and Ophites mackinnoni, is a rare species of non-venomous snake belonging to the family Colubridae. Commonly known as the two-coloured wolf snake, bicoloured wolf snake, golden wolf snake, or Mackinnon’s wolf snake, this species is endemic to the Western Himalayas. It is of particular scientific interest due to its restricted distribution, long period of apparent absence from its type locality, and subsequent rediscovery after more than a century.

Taxonomy and Nomenclatural History

The species was first described in 1906 by the British herpetologist Frank Wall, who named it Lycodon mackinnoni. Subsequent taxonomic treatments placed it under different genera, including Ophites, reflecting historical uncertainty regarding wolf snake classification. Later revisions consolidated the species under the name Lycodon bicolor, which is now widely accepted in modern herpetological literature.
The taxonomic history of Lycodon bicolor reflects broader challenges in the systematics of the genus Lycodon, which includes several morphologically similar species distributed across South and Southeast Asia. Diagnostic characters such as colour pattern, scalation, and geographic isolation have been central to clarifying its status as a distinct species.

Geographic Distribution

Lycodon bicolor is restricted to the Western Himalayas, making it one of the most geographically limited wolf snake species. Its known range extends from Uttarakhand in northern India, westwards through Jammu and Kashmir (now a union territory), and into Azad Kashmir in Pakistan. The species was originally described from Mussoorie, a hill station in Uttarakhand.
Remarkably, after its original description, Lycodon bicolor was not recorded again from its type locality or surrounding regions for over 112 years. This prolonged absence led to speculation that the species might be extremely rare, misidentified, or possibly locally extinct. In 2019, the snake was rediscovered during systematic herpetological surveys in Binog Wildlife Sanctuary, near Mussoorie. These findings were formally reported in 2021, confirming the continued existence of the species in its historic range.

Conservation Context and Threats

The rediscovery of Lycodon bicolor has significant conservation implications. Mussoorie and its surrounding areas are major tourist destinations, characterised by heavy traffic flow, urban expansion, pollution, and tourism-related disturbances. Such pressures pose potential threats to habitat integrity within and around Binog Wildlife Sanctuary.
Given the species’ limited distribution and apparent rarity, herpetologists have emphasised the need for detailed population assessments, habitat evaluation, and long-term monitoring. Further research is essential to determine its conservation status accurately and to inform protective measures aimed at mitigating anthropogenic impacts.

Morphological Description

Adult Lycodon bicolor individuals are moderate-sized snakes. They may attain a total length of approximately 60–70 cm, including a tail measuring around 12–15 cm, though precise measurements vary among specimens.
The dorsal coloration is distinctive, consisting of a brown ground colour overlaid with a network of white lines, giving the snake a reticulated or two-toned appearance that underlies its common name. The ventral surface is typically uniformly white, although some individuals show white ventral scales edged with brown.
The dorsal scales are smooth and arranged in 17 rows at mid-body, a characteristic consistent with other members of the genus Lycodon. The anal scale is divided, which is an important feature for taxonomic identification. As with other wolf snakes, the head is slightly flattened and distinct from the neck, aiding entry into narrow crevices in rocky habitats.

Habitat and Ecology

The preferred natural habitats of Lycodon bicolor include rocky terrain and shrubland, particularly in montane environments. The species is found at mid to high elevations within the Western Himalayan range, though precise altitudinal limits remain poorly documented due to the scarcity of records.
These habitats provide abundant shelter in the form of rock fissures, loose stones, and vegetation cover, which are essential for thermoregulation, concealment from predators, and foraging. The species is presumed to be nocturnal, like other members of the genus, although detailed behavioural studies are lacking.

Behavioural Characteristics

While specific behavioural observations of Lycodon bicolor are limited, it is likely to share behavioural traits with closely related wolf snakes. These typically include nocturnal activity patterns, secretive habits, and a tendency to seek refuge under rocks or within crevices during daylight hours.
Wolf snakes are known for defensive biting when handled, despite being non-venomous. Their sharp, recurved teeth can cause superficial lacerations, which often leads to exaggerated perceptions of danger. There is no evidence that Lycodon bicolor possesses venom or poses any medical risk to humans.

Diet and Feeding Ecology

Direct observations of feeding in Lycodon bicolor have not been documented. However, based on the feeding ecology of the genus Lycodon, it is inferred that the species primarily preys on small reptiles, particularly lizards, and possibly amphibians. The specialised dentition typical of wolf snakes is adapted for gripping smooth-scaled prey, enabling them to extract lizards from narrow retreats.

Reproductive Biology

Lycodon bicolor is an oviparous species, laying eggs rather than giving birth to live young. Specific data on clutch size, breeding season, and incubation period are not yet available. By analogy with related species, reproduction likely occurs during warmer months, with eggs deposited in concealed, moist microhabitats such as under rocks or within soil crevices.
The lack of reproductive data highlights a significant gap in current knowledge and underscores the need for focused ecological studies on this rare Himalayan snake.