Neotropical blunt-headed tree snake, Fiddle-string snake
The Blunthead tree snake (Imantodes cenchoa) is a rear-fanged mildly venomous reptile. It is native to the Americas and is known for its long, slender body and very large head.
The ventral surface, or stomach, of the Blunthead tree snake is mostly white, while the dorsal surface, or top, is a light or pale brown with lateral dark brown patches that begin at the head and continue down the length of the body. The northern and southern populations of the Blunthead tree snake exhibit different sexual dimorphism, the existence of two different traits of a species in the same population. For example, northern males have a slightly longer tail whereas the males of southern populations have a shorter tail. In some regions females typically have a much larger head than males. The pupil of this snake is very distinct from other snakes. Most snakes found around the world are known to have very poor vision and rely mostly on smell and vibrations to detect signs of prey and predators. Arboreal snakes have much better vision than other snakes. The Blunthead tree snake has a vertical slit for a pupil which allows it to look downward. This trait gives the Blunthead tree snake an advantage over other snakes. The large eyes make up approximately 26% of its head.
Blunthead tree snakes are found in Mexico, most of Central America, and parts of South America south to northernmost Argentina. They prefer to live in cooler and moist areas such as wet forests, rainforests, and montane forests. They can also be found in savannas, farms, and cultivated areas.
Blunthead tree snakes are arboreal and most often found in low vegetation such as coffee trees or bromeliads. They are active during the night and rest in a coiled position in very shaded areas during the day. At night they come out to hunt through dense vegetation on the ground up to their resting places in the trees. Outside of the breeding season, they lead a solitary life. They are docile in nature and are not considered dangerous to humans.
Blunthead tree snakes are carnivores. They prey mostly on small lizards such as anoles, frogs, and reptiles and amphibian eggs.
Blunthead tree snakes are polygynandrous (promiscuous) meaning both the males and females have multiple partners during the breeding season. Some snakes mate year-round, but the mating season of others may be synchronized with the wet and rainy seasons of their environment. Blunthead tree snakes are oviparous or egg-laying reptiles. In Guatemala and Mexico, females lay their eggs between June and July. These eggs will hatch around July and August, which are the typically rainy seasons in these countries. On the other hand, snakes in Brazil exhibit continuous reproduction. The eggs are laid from November to January and start to hatch around March throughout August. The female can lay from 1 to 3 eggs. The female will leave her eggs after laying them and doesn't provide parental care traits. Both males and females become reproductively mature about 2 years after hatching or at around 620 mm (24 in) SVL (snout-to-vent length).
There are no major threats to this species at present.
According to the IUCN Red List, the Blunthead tree snake is locally common throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
