Natrix helicops

Natrix helicops, also known as the brown-banded water snake, is a species of aquatic snake found in tropical South America and Trinidad and Tobago. It is a medium-sized snake, reaching a maximum total length of 78 cm (31 inches). It is olive or gray-brown in color, with dark brown, black-edged crossbands. The belly is yellowish or white with black crossbands or black spots.

DIAGNOSTIC CHARACTERS

Body: 

Medium-sized, up to 78 cm (31 inches) in total length.

Color:

Olive or gray-brown with dark brown, black-edged crossbands. The belly is yellowish or white with black crossbands or black spots.

Head:

Relatively small, with a broad snout.

Eyes: 

Large, with round pupils.

Scales: 

Smooth, with 17 rows of midbody scales.

Vent: 

Single.

Sexual dimorphism: 

Males are slightly larger than females.

REPRODUCTION

Natrix helicpos is ovoviviparous, meaning that the young hatch from eggs inside the mother's body. The female gives birth to a litter of 6-12 young, typically in the spring or summer. The young are born fully developed and independent.

• The breeding season for Natrix helicpos is thought to be from January to April. The males court the females by following them and rubbing their chins on their bodies. Once the female is receptive, the male will mount her and mate.

• The eggs are fertilized inside the female's body, and they hatch about 60-70 days after fertilization. The young snakes are born live, and they are about 10-12 cm (4-5 inches) long at birth.

• The young snakes are independent from birth, and they start to eat small fish and amphibians. They reach sexual maturity at about 2 years old.

• The female's body temperature can affect the sex of the young. If the female's body temperature is high, the young will be more likely to be male.

• The young snakes are born with a yolk sac that provides them with nutrients for the first few days of life.

• The young snakes are very vulnerable to predators, and their survival rate is low.

SIZE

Size of Natrix helicpos varies depending on the individual snake and the population, but they typically reach a maximum total length of 78 cm (31 inches). The average size for adults is 50-60 cm (20-24 inches). The smallest snakes are typically found in populations that live in colder climates.

MORPHOLOGY

Dorsal: 

The dorsal side of Natrix helicpos is olive or gray-brown, with dark brown, black-edged crossbands. The crossbands are wider than the spaces between them. The head is slightly darker than the body, and the snout is pointed.

Ventral:

The ventral side of Natrix helicpos is yellowish with black crossbands or black spots. The belly is smooth, and the scales are undivided.

The dorsal and ventral coloration of Natrix helicpos helps to camouflage the snake against the background of rocks and vegetation. The dark brown, black-edged crossbands on the dorsal side help to break up the outline of the snake, making it difficult to see. The yellowish ventral side helps the snake to blend in with the sand or mud on the bottom of rivers and streams.

Head: 

• The head of Natrix helicpos is elongated, with a distinct neck. The snout is pointed, and the eyes are large, with round pupils. The scales on the head are smooth, with a keel on the dorsal scales.

• The head of Natrix helicpos is well-adapted for its aquatic lifestyle. The elongated snout allows the snake to probe into crevices and under rocks in search of prey. The large eyes with round pupils allow the snake to see well in both bright and dim light. The keeled dorsal scales on the head provide traction when the snake is climbing on rocks or other surfaces.

Tail:

• The tail of Natrix helicpos is long and slender, and it tapers to a point. The tail is about one-third of the total length of the snake.

• The tail of Natrix helicpos is also well-adapted for its aquatic lifestyle. The long and slender tail helps the snake to swim easily, and the tapering tip helps the snake to steer. The tail is also used for defense. If the snake is threatened, it may whip its tail at the predator, which can startle or even injure the predator.

ECOLOGY

Natrix helicpos is a semi-aquatic snake that is found in freshwater habitats in South America, including rivers, streams, lakes, and swamps. They are also found in some areas of coastal freshwater.

BEHAVIOUR

Ambush predator: 

Natrix helicpos is an ambush predator that waits for prey to come to it. They will often lie in wait on rocks or logs near the water's edge, or they may swim underwater and wait for prey to swim by.

Aggressor: 

Natrix helicpos is known to be aggressive when threatened. They will often flatten their bodies and spread their crossbands, making them appear larger and more intimidating. They may also hiss and vibrate their tails. If the threat persists, the snake may bite.

Solitary: 

Natrix helicpos is a solitary snake, but they will sometimes gather in large groups during the breeding season.

Diurnal:

 Natrix helicpos is active during the day and night, but they are most active during the day.

Good swimmer: 

Natrix helicpos is a good swimmer and can stay underwater for up to 30 minutes.

Climber: 

Natrix helicpos is also a good climber and can climb trees and rocks.

Oviparous:

 Natrix helicpos is oviparous, meaning that they lay eggs. The females lay a clutch of 6-12 eggs, which hatch after about 60-70 days.

Independent:

 The young snakes are independent from birth and do not receive any parental care.

TROPHIC STRATEGY

• The trophic strategy of Natrix helicpos is that of an opportunistic predator. This means that they are not specialized to eat any particular type of prey, but rather they will eat whatever is available.

• Their diet consists mainly of aquatic animals, including fish, frogs, tadpoles, and small mammals. They will also eat small birds and reptiles.

VENOMOSITY

Natrix helicpos is a non-venomous snake. It does not have any venom glands, and its bite is not harmful to humans. However, the snake may still bite if it feels threatened. The bite may cause some pain and swelling, but it is not serious.

GENERAL HABITAT

• Natrix helicpos is a semi-aquatic snake that is found in freshwater habitats in South America, including rivers, streams, lakes, and swamps. They are also found in some areas of coastal freshwater.

• The ideal habitat for Natrix helicpos is a slow-moving body of water with plenty of cover, such as rocks, logs, and vegetation. They prefer habitats with sandy or muddy bottoms, as this makes it easier for them to burrow.

• Natrix helicpos is not found in high altitudes or in areas with extreme temperatures. They are most common in tropical and subtropical regions, but they can also be found in some temperate regions.