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Colubridae

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Colubridae is the largest family of snakes in the world.

Coast Garter Snake
Coast Garter Snake

This massive group contains 249 different genera. These snakes are found on every continent except for Antarctica. They live in many different environments. Some species live in deserts or high mountains. Others live in water or in trees. Some even live underground or in brackish waters. This diversity allows them to thrive in many different habitats.

Most colubrids are shy and harmless to humans. The vast majority of these snakes are not venomous. Even when they do have venom, it often does not impact mammals. However, some bites can become medical emergencies. The South African boomslang and twig snakes are known for dangerous bites. Asian keelback snakes are also noted for causing harm. These specific species have caused the most confirmed human fatalities.

Some colubrids use special teeth to hunt. These snakes are described as opisthoglyphous, or rear-fanged. This means they have short, grooved fangs at the back of the upper jaw. These fangs are often sharp on both the front and back edges. To inject venom, the snake must chew on its prey. This chewing motion creates a cutting action against the tissue. This trait may be an evolutionary precursor to the front fangs found in vipers.

Sibon longifrenis (La Selva Biological Station)
Sibon longifrenis (La Selva Biological Station)

Other colubrids are proteroglyphous, meaning their fangs are at the front of the upper jaw.

Colubrids have many unique physical traits. They have limbless bodies and a reduced or absent left lung. Some possess a tracheal lung to help them breathe. Their anatomy includes well-developed oviducts for reproduction. Their upper jaw bones, called premaxillaries, lack teeth. The maxilaries are oriented longitudinally with teeth that are either solid or grooved. They also lack cranial infrared receptors. Instead, their optic foramina typically traverse specific sutures in the skull.

These snakes have different ways of reproducing. Most colubrids are oviparous, which means they lay eggs. The size of the egg clutch depends on the species and size of the snake. However, some subfamilies are viviparous. This means they give birth to live young. This occurs in the Natricinae and Colubrinae subfamilies. The number of offspring born live also depends on the specific snake species.

Scientists have changed how they classify these snakes over time. In the past, Colubridae was called a "wastebasket taxon." This meant scientists put snakes in this group if they did not fit elsewhere. Some snakes in the group were actually more related to elapids. Recent research in molecular phylogenetics has changed this. This study of DNA has helped create a monophyletic clade. This means the current group shares a common ancestor.

Indian Rat Snake (Grey and Yellow)
Indian Rat Snake (Grey and Yellow)

As of May 2018, there are eight recognized subfamilies. The Dipsadinae subfamily is very large with over 100 genera.

The Colubrinae subfamily contains 93 genera. The Natricinae subfamily includes 36 genera. Other subfamilies include Sibynophiinae, Pseudoxenodontinae, Grayiinae, and Calamariinae. Some subfamilies are still being determined by researchers. This classification helps us understand the complex relationships between different snakes.

The history of colubrids is visible in the fossil record. The earliest fossils date back to the Late Eocene epoch. Some indeterminate vertebrae were found in Thailand. Other fossils, belonging to the genus Nebraskophis, were found in Georgia, USA. Because these fossils appear in North America so early, scientists think they may have originated even earlier.

Other fossils from the Pliocene were found in the Ringold Formation in Washington. These included the extinct genus Tauntonophis and species like Elaphe pliocenica.

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🖼️ Images & Media (5)
File:Texas Patch-nosed Snake, Enchanted Rock State Natural Area, Fredericksburg, TX, US imported from iNaturalist photo 368120695.jpg
Texas Patch-nosed Snake, Enchanted Rock...
File:Indian Rat Snake (Grey and Yellow).jpg
Indian Rat Snake (Grey and Yellow).jpg
File:Coast_Garter_Snake.jpg
Coast_Garter_Snake.jpg
File:Sibon_longifrenis_(La_Selva_Biological_Station).jpg
Sibon_longifrenis_(La_Selva_Biological_Sta...
File:PikiWiki Israel 37648 Nature and Colors.jpg
PikiWiki Israel 37648 Nature and Colors.jpg
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