tortoises.
Snakes or serpents (the latter usually referring to a mythic or symbolic snake) are associated
with healing in the Bible (the account of the brass serpent of Moses) as well as with the devil
(the Biblical account of Adam and Eve). The periodic renewal, as in the shedding of snake
skin, has led to the snake being a symbol of healing and medicine, as pictured in the Rod of
Asclepius (Figure13.31). In Egyptian history, the snake occupies a primary role with the
Nile cobra adorning the crown of the pharaoh in ancient times. It was worshipped as one of
the gods and was also used for sinister purposes, such as murder of the adversary and ritual
suicide by the Egyptian queen Cleopatra. Snakes also play a role in Greek mythology, in
Indian tradition and religion, and in other religions and customs.
Lesson Summary
- Reptiles are air-breathing, cold-blooded vertebrates characterized by a scaly skin.
- Reptiles have a variety of reproductive systems, with different strategies for providing
nutrition to developing young. - Lizards and snakes are distinguished by a unique type of scaly skin and movable
quadrate bones. - There is a tremendous variety in color, appearance and size of lizards, and they have
some unique adaptations, including regeneration of lost limbs or tails and changing
color. - Snakes are distinguished by lack of eyelids, limbs, external ears and vestiges of fore-
limbs. - Snakes have various adaptations for killing and eating their prey.
- Crocodiliahaveaflexiblesemi-erectposture, thecodontdentition, replacementofteeth,
and a secondary bony palate. - The sex of developing crocodilians is determined by the incubation temperature of the
eggs. - Other crocodilian traits, such as salt glands, nictitating membranes, ear flaps and
sensory pits, are adaptations for aquatic living. - Turtles are characterized by a special bony or cartilaginous shell; have specialized
adaptations for aquatic living, such as eye placement and salt glands, and adaptations
for terrestrial living as well (placement of eyes and protection of eggs). - Reptilesplayimportantrolesaspredatorsofpestspecies, foodsources, pets, inmedical
and scientific research, and in folklore, religion and popular culture.
Review Questions
- Describe the general traits of reptiles.
- Describe the different types of reproduction in reptiles.
- How are snakes distinguished from legless lizards?