- Also called:
- mangrove cat snake, gold-ringed cat snake, or yellow-ringed cat snake
- Related Topics:
- mangrove snake
Black-and-yellow mangrove snake
Where is the black-and-yellow mangrove snake found?
What is the conservation status of the black-and-yellow mangrove snake?
What is denmotoxin?
Is the black-and-yellow mangrove snake venomous?
Black-and-yellow mangrove snake, (Boiga dendrophila), species of mangrove snake native to Southeast Asia. The animal is named for the distinctive yellow-colored bands across its black body. Its venom is only mildly toxic to mammals but is highly lethal to birds, which constitute the snake’s main prey.
Distribution and description
The nine recognized subspecies of Boiga dendrophila—which together form the informal Boiga dendrophila complex—are listed below. The countries or regions where these subspecies have been documented are also listed.
- Boiga dendrophila dendrophila (Indonesia)
- Boiga dendrophila divergens (Philippines)
- Boiga dendrophila gemmicincta (Indonesia)
- Boiga dendrophila latifasciata (Philippines)
- Boiga dendrophila levitoni (Philippines)
- Boiga dendrophila multicincta (Philippines)
- Boiga dendrophila occidentalis (Indonesia)
*Research from 2020 suggests that this could be considered a full species, Boiga melanota.
This member of the Colubridae family of snakes is found in mangrove swamps and tropical lowland forests from the Malay Peninsula to the Philippines. Its average length is about 2 meters (6.6 feet), although specimens measuring 2.5 meters (8.2 feet) have also been reported. The body of the black-and-yellow mangrove snake is uniformly black or black above and bluish below, with transverse yellow bands circling its entire length. The bands may or may not be complete on the back. The lips and throat of the animal are also yellow with black edges. As with other members of the Boiga genus, the black-and-yellow mangrove snake also has elliptical pupils, which have earned the genus the nickname “cat-eyed snakes.”
Similar to other colubrids, this species possesses a Duvernoy’s gland—a venom gland located behind the eyes and connected by a tube to grooved, backward-curving teeth at the back of the upper jaw. The venom secreted by the gland is called denmotoxin: It is a postsynaptic neurotoxin that specifically binds with nicotinic acetylcholine receptors in the muscles of birds, thereby blocking neuromuscular transmission and paralyzing the prey. The venom is mildly toxic to mammals such as mice, and it is reported to only cause inflammation and skin discoloration in humans.
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Snakes specialize in swallowing large prey whole. They achieve this by using their flexible skull and unfused lower jaws that are connected by elastic ligaments—not by dislocating their jaws, as is commonly believed. The process is driven by a feeding mechanism called the pterygoid walk, in which alternating jaw movements advance one side of the tooth-bearing upper jaw while the other maintains a firm grip on the prey. By repeatedly alternating this ratcheting motion between the left and right sides, the snake effectively “walks” its head over the prey, pulling it down the throat.
Natural history
The specific name of this snake indicates its arboreal nature: Dendrophila is derived from the Greek words dendron (“tree”) and phil (“love”). This species spends most of its time coiled around tree branches more than 30 meters (100 feet) high, descending during the night to prey on birds, small mammals, frogs, and other reptiles on the forest floor. It is equally adept at hunting from tree branches: It coils into the shape of an S before lunging at prey or in defense against a predator.
These snakes lay 4–15 eggs in tree hollows, which hatch in about 45 days. Their young measure about 20–30 cm (7.9–11.8 inches) in length and are similarly colored to the adults. Black-and-yellow mangrove snakes are able to hunt independently soon after hatching. They are kept as pets, although keeping them may require special permits in some regions. They can reportedly live for up to 20 years in captivity.
Conservation status
According to its 2019 assessment, the International Union for Conservation of Nature and Natural Resources classifies the black-and-yellow mangrove snake as a species of least concern, suggesting that it is not under any perceivable threat. However, its natural habitat is at risk of degradation because of human activities such as aquaculture, conversion of forest and wetlands into farmlands, and infrastructure development. The species has considerable economic value as a pet, and its toxin is a source of pharmacologically important biochemicals. Some experts claim that this could make the species vulnerable to unregulated and illegal trade.