AGKISTRODON (PIT VIPERS)

Contents hide

1) Introduction

2) Classification of Agkistrodon (Pit Viper)

3) Geographical distribution

4) Habit and habitat

5) General Characteristics of Agkistrodon (Pit Viper)

6) Ecological Importance

7) Conservation Status

8) Special features

9) Identification

Introduction

The genus Agkistrodon refers to venomous pit vipers, including the well-known copperheads and cottonmouths, native to North America. These snakes are recognized for their heat-sensitive pit organs, enabling them to detect warm-blooded prey. They inhabit a variety of environments, from forests and swamps to rocky hillsides. Agkistrodon snakes are vital predators within their ecosystems, contributing significantly to ecological balance.

Classification of Agkistrodon (Pit Viper)

Phylum :- Chordata (Dorsal tubular nerve cord, notochord and gill-slits present.)
Group :- Craniata (Definite head, Cranium with brain present.)
Sub phylum :- Vertebrata (Vertebral column present.)
Division :- Gnathostomata (Jaws and paired appendages present.)
Super Class :- Tetrapoda (Paired limbs, lungs, cornified skin and bony skeleton.)
Class :- Reptilia (Scaly vertebrates. Right and left aortic arches present. Single condyle. Pulmonary respiration. Embryo with amnion and allantois.)
Sub Class :- Diapsida (Skull with two temporal openings separated by post-orbital and squamosal.)
Order :- Squamata (Lizards and snakes with horny epidermal scales or shields. Quadrate bone movable. Vertebrae procoelous. Anal opening transverse.. Vertebrae amphicentrous.)
Sub-order :- Ophidia (Snakes. Limbs, feet, ear openings sternum and urinary bladder absent. Mandibles jointed anteriorly by ligament. Tongue slender, bifid and protrusible. Left lung reduced.)
Family :- Viperidae (Paired erectile fangs in front of upper jaw.)
Genus :- Agkistrodon

Geographical distribution

Agkistrodon species are primarily found in North America, with their range extending into parts of Central America.
Key Regions:
- United States:
  - Copperheads are found in the eastern and central U.S., ranging from New England to Texas.
  - Cottonmouths are more prevalent in the southeastern U.S., particularly in wetland-rich states like Florida, Georgia, and Louisiana.
- Mexico and Central America:
  - Some species are distributed in the southernmost regions of North America and parts of Central America.
Elevation Range: Typically found at low to moderate elevations but can adapt to higher altitudes depending on the habitat conditions.

Habit and habitat

Agkistrodon species, which are now largely reclassified under the genus Agkistrodon, inhabit diverse ecosystems across their range.
Preferred Environments:
- Forests and Woodlands: Found in deciduous forests with ample leaf litter for camouflage.
- Swamps and Wetlands: Cottonmouths (Agkistrodon piscivorus), a member of this genus, thrive in wetland areas, including swamps, marshes, and riverbanks.
- Rocky and Hillside Areas: Copperheads (Agkistrodon contortrix) are often found in rocky outcrops, forest edges, and hillside habitats.
- Grasslands and Fields: Occasionally found in open areas with adequate ground cover.
Nesting and Shelter:
- They use burrows, hollow logs, and crevices for shelter and nesting. These areas provide protection from predators and extreme weather.

General Characteristics of Agkistrodon (Pit Viper)

Commonly called as Himalayan pit viper. Body is not much elongated, measures about 1 metre in length. Body divided into head, neck, trunk and tail. Colour is bluish brown with dark brown or black spots which appear like crossbars. Head is triangular containing nostrils, eyes and mouth. A characteristic loreal pit in present on each side of upper jaw separating eye and nostril. Head shields are large
Upper lip is slightly raised in rostral region, post-ocular two, supra-ocular enlarged sideways to form shield over the eye and pre-ocular three in number.
Eyes are big with golden iris and vertical pupil

Classification of Ancistrodon (Pit Viper) — Image Source : IStock

Ecological Importance

Prey Regulation: Agkistrodon snakes control populations of small mammals, amphibians, and insects, preventing overpopulation and crop damage.
Seed Dispersal Support: By preying on seed-eating rodents, they indirectly contribute to vegetation propagation and forest regeneration.
Food Chain Role: They are prey for larger predators such as birds of prey, coyotes, and larger snakes, maintaining the balance of the food web.
Pest Control: Their predation on rodents reduces the spread of diseases such as Lyme disease and hantavirus

Conservation Status

Global Status: Species within the genus (or now Agkistrodon) are generally listed as Least Concern, though some local populations face threats from habitat loss and persecution.
Threats:
- Habitat destruction due to urbanization and agriculture.
- Direct killings by humans due to fear and misunderstanding.
Conservation Efforts: Protected under various regional wildlife laws to prevent overhunting and habitat encroachment. Education campaigns to reduce human-snake conflict

Special features

Pit viper is a shy and alert snake. Even on slight disturbance it runs back to its shelter.
It is a poisonous snake having well-developed, erectile poisonous and sheathed fangs.
Heat-Sensitive Pits: Located between their eyes and nostrils, these pits detect infrared radiation, allowing them to hunt effectively in the dark.
Venom Adaptation: They produce hemotoxic venom, which immobilizes prey and aids in digestion, though it is rarely fatal to humans.
Camouflage: Their coloration blends seamlessly with leaf litter and forest floors, providing excellent concealment from predators and prey.
Ambush Predators: These snakes often lie in wait for prey, conserving energy and striking with precision.
Defensive Behavior: When threatened, Agkistrodon species exhibit warning behaviors such as coiling, vibrating their tails, and emitting musk to deter predators.