Page 45 - Reptiles & Dinosaurs (Britannica Illustrated Science Library)

40 REPTILES: BACKGROUND REPTILES AND DINOSAURS 41

A Menu at Ground Level Carnivores

The tools in a predator reptile's kit include an
opportunistic instinct, well-developed reflexes,
SNAKES
eptiles are basically carnivorous, even though some follow other food regimens. can expand both their mucous glands in the mouth that lubricate its
Lizards usually feed on insects. Snakes usually feed on small vertebrates like birds, mouths and parts of their prey, a potent immune system, and a tongue
with olfactory nerve endings.
digestive tracts to swallow
R rodents, fish, amphibians, or even other reptiles. For many, the eggs of birds and their prey whole. Their teeth
and fangs are not for
other reptiles make a very succulent meal. The painted turtle is omnivorous: it eats chewing but for hunting,
meat and plants. Reptiles and other species are part of a larger food chain—animals poisoning, and retaining
their prey.
eat other animals, preserving the equilibrium of the environment.
X-RAY IMAGE
This snake swallowed CROCODILES
a frog whole. feast on invertebrates
and other vertebrates.
Crocodile young mainly
consume terrestrial and
aquatic invertebrates,
Herbivores whereas the adults feed
primarily on fish.
This diet is generally typical of other groups of
animals; however, there are reptiles that feed
only on green leaves and plants. The marine
iguana eats only the algae that it finds under
rocks on the sea floor. BOAS
POISONOUS
SNAKES
GREEN IGUANA
Also called the common iguana, THIRD LEVEL CROCODILES
it is one of the few herbivorous
reptiles. It feeds on green leaves
as well as on some fruits.
RODENTS
CHAMELEON
SMALL
BIRDS
SMALL LIZARDS
SECOND LEVEL INSECTS

IGUANAS
SNAILS
WOOD TURTLE
Clemmys insculpta
GAZELLES
Omnivores
LAND TURTLES Turtles may be slow, but many include mollusks,
FIRST LEVEL worms, and slow-moving insect larvae among the
items on their otherwise vegetarian menu. The
loggerhead sea turtle, which measures over 6.5
feet (2 m) long, eats sponges, mollusks,
PRODUCERS
crustaceans, fish, and algae.
The Food Chain
Because they use photosynthesis, which animals that feed on the herbivores are second-
permits inorganic carbon to be transformed level consumers, and the animals that eat other
into organic material, plants are the only true carnivores—a category that includes some
“producers” in the food chain. Herbivores feed on reptiles—form the third level of consumers in the
them and are thus first-level consumers. The food chain.
GREEN IGUANA
Iguana iguana
Metabolism

In the case of snakes that swallow their prey
whole, digestion takes weeks and sometimes
even months. Their gastric juices digest even
the bones of their prey. EYELASH VIPER
Bothriechis schlegeli