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Snakes – Part 1

Herpetoculture

Pensacola Jr College

Snakes -- Classification

w Phylum Chordata

w Subphylum Vertebrata

w Superclass Tetrapoda

w Class Reptilia

w Order Squamata

w Suborder Serpentes

SQUAMATES –
REVIEW

Order Squamata

w Lizards, snakes, amphisbaenians

w High degree of skull kinesis

w Hemipenes with sulcus spermaticus groove in each

w Scales of varying shapes and sizes

Order Squamata (cont’d)

w Limb reduction common

w Often have caudal autotomy

• Lose tail voluntarily

• Fracture planes within vertebra

• Muscle and connective tissue arrangement allow easy split

• Tail regrowth with cartilage rod in lizards (not snakes)

Order Squamata (cont’d)

w Transverse anal opening

w Jacobson’s organ in roof of mouth (chemosensory)

THE SNAKES

Suborder Serpentes

w Physical characteristics:

• Legless

• Bone reduction and loss of articulations in skull

• Highest degree of skull kinesis

• Long slender curved pleurodont teeth, some with specialized adaptations (fangs)

• No eyelids or ear openings

Suborder Serpentes

w Physical characteristics:

• Spectacle / brille covers eye, shed with skin (ecdysis)

• Well developed Jacobson’s organ

• Long deeply forked tongue

• Most have heat sensors, some developed into pits on face or lips

Bluing of eyes

Ecdysis

Suborder Serpentes

w Physical characteristics:

• Over 200 vertebrae, each with a long pair of ribs attached

• Internal organs elongated

• One of each paired organ is reduced, lost, or offset from each other

• Long, flexible, scaly body

SNAKE ANATOMY

Suborder Serpentes

w Four modes of locomotion:

• Rectilinear motion = individual movement of ventral scutes

• Lateral undulation = faster S-shaped movement

• Concertina motion = accordion style (climbing or movement through narrow space)

• Sidewinding = body thrown in air in sideways arcs

Rectilinear motion

Lateral undulation

Concertina motion

Sidewinding

Suborder Serpentes

w Carnivorous

• some insectivores, egg-eaters

w Solitary

• except while denning in some winter groups

w Reproduction:

• One hemipene used for mating

• Egg-laying or live-bearing

• No parental care of young

Classification

w Class Reptilia

w Order Squamata

w Suborder Serpentes

• Family Pythonidae

• Family Boidae

• Family Typhlopidae

• Family Colubridae

• Family Elapidae

• Family Viperidae