Lycodon Aulicus

Lycodon aulicus, commonly known as the Indian wolf snake or common wolf snake, is a species of non-venomous colubrid snake widely distributed across South Asia and parts of Southeast Asia. Despite its harmless nature, it is frequently misidentified as the highly venomous common krait due to similarities in colour pattern and body form. This resemblance led early naturalists to suggest Lycodon aulicus as a classic example of Batesian mimicry, in which a non-venomous species gains protection by imitating a dangerous one.

Taxonomy and Scientific Background

The species belongs to the genus Lycodon, commonly referred to as wolf snakes, characterised by their elongated bodies and specialised dentition adapted for gripping prey. The species was formally described during the nineteenth century, with detailed accounts provided by Albert Günther in Reptiles of British India (1864) and later expanded by George Albert Boulenger in The Fauna of British India (1890) and the Catalogue of the Snakes in the British Museum (1893). These classical works remain foundational for understanding the morphology and variation of the species.

General Description and Morphology

Lycodon aulicus is a medium-sized snake with a broad, much-depressed snout and a distinctly spatulate shape in adults. The upper lip is swollen, and there is no well-defined canthus rostralis. The rostral shield is low and broad, barely visible from above, while the internasals are very small compared to the elongate prefrontals, particularly in adult specimens.
A distinctive feature useful for identification is the presence of a single large loreal shield, nearly twice as long as broad. This loreal shield is absent in kraits, making it a key diagnostic character. The praeocular is usually single and often contacts the frontal, with two postoculars present. The upper labials number nine, with the third, fourth, and fifth entering the eye.
The scales are smooth, arranged in 17 rows around the mid-body, often bearing a minute apical groove. The ventral scales are obtusely angulate laterally, producing a subtle ridge along the abdomen and tail.

Dentition and Feeding Adaptations

Although non-venomous, Lycodon aulicus possesses a specialised dentition that contributes to its reputation for fierce biting. Each maxilla bears two enlarged anterior fangs, arranged transversely, followed by a series of smaller teeth. These fangs are not associated with venom delivery but are well adapted for gripping slippery or smooth-scaled prey.
According to Günther, this dental arrangement makes the species a particularly effective predator of skinks, whose smooth, hard scales require a firm grip. Additional teeth occur on the pterygoid and palatine bones, while the mandible bears two or three enlarged teeth on each side.

Colouration and Intraspecific Variation

The colouration of Lycodon aulicus is highly variable, contributing to frequent misidentification. Patterns range from uniform brown to complex banded or reticulated forms. Günther identified several varieties based on regional and morphological differences.
Continental varieties include:

• Uniform brown individuals without a collar.
• Uniform brown specimens with a distinct white collar.
• Brown or greyish-brown forms with faint white reticulation and a collar, more prominent in juveniles.
• Ferruginous or chestnut-brown forms with white, brown-edged crossbars, often bifurcated laterally, forming a collar at the neck.

Ceylonese varieties show more elongate posterior frontals and include:

• Uniform brownish-grey specimens.
• Brown forms with broad white crossbands on the anterior body.
• Brown or grey individuals with bright white or reticulated bands extending to the belly.

The lower surface is generally uniform white, while the upper lip may be plain white or spotted with brown.

Scalation Measurements

Scalation is an important feature for taxonomic identification. Typical counts include:

• Ventrals: approximately 170–224
• Subcaudals: 56–80, divided
• Anal shield: divided

The frontal shield touches the parietals, supraoculars, prefrontals, and preoculars, while the parietals are notably larger than the frontal.

Distribution and Habitat

Lycodon aulicus has a wide geographic range, occurring in Pakistan, India, Sri Lanka, Nepal, Bangladesh, Myanmar (Burma) and extending into parts of Southeast Asia, including the Malay Peninsula, Thailand, Java, the Philippines, and Timor. In India, it is found from the plains to the Himalayan foothills and Assam.
It is considered one of the most common snakes in India and Sri Lanka, though it becomes less frequent along the south-eastern coastal regions. The species occupies a variety of habitats, including forests, agricultural land, rocky areas, and human settlements, where it is often encountered near houses at night.

Behaviour and Defensive Strategies

The Indian wolf snake is strictly nocturnal, remaining inactive during daylight hours. It is known for its aggressive defensive behaviour when threatened or cornered. Although harmless, it can inflict painful lacerations with its sharp teeth if handled carelessly.
In addition to biting, the species may exhibit thanatosis, or feigning death, a behaviour believed to deter predators or create opportunities to escape. Its active night-time habits and tendency to enter human dwellings in search of prey contribute to its frequent encounters with people.

Diet and Ecological Role

The diet of Lycodon aulicus consists mainly of lizards and frogs, with skinks forming a major component. Its feeding behaviour plays an important ecological role in regulating populations of small reptiles, particularly in urban and semi-urban environments.
The species’ ability to thrive in disturbed habitats highlights its adaptability and importance within local ecosystems.

Reproduction and Life Cycle

Females are often larger than males and breed prior to the onset of the monsoon season. Clutch sizes typically range from four to eleven eggs. The eggs hatch in September or October, producing hatchlings that are already well-patterned and capable of independent survival.
Reproductive timing is closely linked to climatic conditions, ensuring that hatchlings emerge during periods of increased prey availability.