Pacific Coast Parrot Snake

Pacific Coast Parrot Snake, Leptophis diplotropis

Pacific Coast Parrot Snake, Leptophis diplotropis. Photograph taken within a residential community in the greater Alamos area, Alamos, Sonora, May 2018. Photograph and identifications courtesy of David F Smith, Alamos, Sonora.

The Pacific Coast Parrot Snake, Leptophis diplotropis, is a member of the Colubridae family of North American Racers, Coachwhips, and Whipsnakes. The Colubridae Family comprises two-thirds of the world’s snake population with approximately 2,000 species placed in 249 genera. Many Colubrids are classified as venomous but very few are considered to be dangerous to humans. There are twelve species in the Leptophis genus. The Pacific Coast Parrot Snake is known in Mexico as Ratonera de la Costa del Pacifico.

Pacific Coast Parrot Snakes have long, thin bodies and large elongated heads. They are green or blue-green in color dorsally with a light yellow ventral surface. Their dorsal scales are outlined in black and two black stripes extend caudally from their eyes along their body. Their eyes are large and yellow with round pupils. They have nineteen maxillary teeth and their last two posterior teeth are enlarged. Males can reach up to 90 cm (2 feet 11 inches) in snout-to-vent length with an additional tail length of up to 51 cm (20 inches). Females, which are slightly smaller than the males, and may reach up to 73 cm (2 feet 5 inchesn) in snout-to-vent length with tail lengths up to 37 cm (15 inches).

The Pacific Coast Parrot Snake is diurnal, oviparous, and reproduction occurs during the rainy season. Additionally, their diet consists of frogs, birds, and small lizards. While they are primarily arboreal, this species can also be found on the ground. The Pacific Coast Parrot Snake is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, habitat use, and reproduction.

The Pacific Coast Parrot Snake is endemic to Mexico and occurs from Chihuahua and Sonora southward along the Pacific Coast to Oaxaca. They are found from sea level to elevation of 1,600 m (5,200 feet). They are a highly adaptable species and can be found in a variety of habitats including tropical dry forest, semi-deciduous forest, mangrove forest, oak forest, and wet forest. Additionally, they can be found in areas that have be disturbed by human development.

The Pacific Coast Parrot Snake may be confused with the Green Parrot Snake, Leptophis ahaetulla, due to their similar appearances and overlapping ranges. These species can be differentiated visually. The Green Parrot Snake has a large, elongated, and triangular-shaped head that is distinct from its neck. Additionally, each side of their head is marked with a black streak that passes through their eye. 

From a conservation perspective, the Pacific Coast Parrot Snake is currently considered to be of Least Concern with a large range and apparently stable population. There is some deforestation in parts of their range for agricultural expansion and human settlement. However, this is an adaptable species and deforestation is not likely to be a significant threat currently.