Page 50 - Reptiles & Dinosaurs (Britannica Illustrated Science Library)
P. 50

46 LIZARDS AND CROCODILES                                                                                                                                                                           REPTILES AND DINOSAURS  47




          Lizards                                                                                     DAY GECKOS                  4,765                 Heloderma

                                                                                                      Phelsuma sp.
                izards are the largest group of reptiles. They                                                                    LIZARD SPECIES        comprise only two species, which live in
                                                                                                                                                        the United States and Mexico. They feed
                live in most environments except for extremely                                                                    EXIST IN THE WORLD.   on invertebrates and small vertebrates.          COLORS
                                                                                                                                                                                                         warn of
                                                                                                                                                        Their bodies are massive, and their skin is
          L cold regions, since they cannot regulate their                                                                                              covered with small knobs. They are the           poison.
          own body temperatures. There are land-dwelling,                                                                                               only poisonous lizards, and their bite can
                                                                                                                                                        be dangerous to humans.
          underground, tree-dwelling, and even semi-aquatic                                                                                                                                                    GILA
                                                                                                                                                                                                               MONSTER
          lizards. They can walk, climb, dig, run, and even glide.                                                                      NOSTRIL                                                  FAT TAIL      Heloderma
          Lizards often have differentiated heads, movable                                                                                                                                       stores fat    suspectum
                                                                                                                                                                                                 reserves
          eyelids, a rigid lower jaw, four five-toed feet, a long                                                                                                       EYE WITH EYELID          for later
          body covered with scales, and a long tail. Some can                                                                                                                                    consumption.
          even shed their tails when threatened.                                    STICKY                                                                                   EAR                           Body Heat
                                                                                      TOES
                                                                                                                                                                                                            Lizards survive in environments where they
                                                                                                                                                                             MOUTH                          can maintain their body temperature, such
                                                                                                                                                                                                            as forests or deserts.
                                                                                                                                                                                          CREST                              SUNBATHING
                                                                                                                                                                                          runs from head
          Chameleons               Camouflage                          LIFESAVING RECOURSE          AUTOTOMIC TAIL                                                                        to tail.                           6:00 AM
                                                                                                                                                                                                                             The lizard places
                                                                       Between each vertebra,
          live in Africa, especially in  is an adaptive advantage. By blending in with the  there are rupture planes  Certain lizards can shed                                            SKIN                               its body in the
                                                                                                                                                                                                                             sun's rays to take
          southeastern regions and on  vegetation surrounding them, lizards can escape  enabling the tail to  their tails many times                                                      has scales                         advantage of
          Madagascar. They live in forests,  the notice of both their predators and their prey.  separate from the body.  during their lives. In dangerous                                covered with a                     their heat.
          where they use their prehensile                                                    situations, they may even shed it     CREST                                                  tough, corneous
          tails and toes to climb trees. Their                                              voluntarily in order to flee their                                                            (or hornlike)
          well-known ability to change color                                                confused predators. Later the tail                                                            layer.
          is important when they face                                                       grows back.                                                                                                                      IN ACTION
          danger or when they                                                                                                                                                             SUBTYMPANIC                        10:00 AM
          begin to court.                                                                                                                                                                 SHIELD                             It begins its daily
                                                                                                                                                                                                                             activities and
                                                                                                                                                                                                                             movements.
                                                                   TELESCOPIC   Geckos
                                                                   EYES
                                                                                and Skinks
                                                                                                                                                                                          DEWLAP
                                                                                are lizard-like animals of the family                                                                     is fleshy and                      HIDDEN
                                                                                Gekkonidae that live in warm                                                                              large in males.                    12:00 PM
                                                                                regions. Their limbs are very                                                                                                                When the sun is at
                                                                                small. (In fact, some                                                                                                                        its highest, they
                                                                                species have none at                                                                                                                         hide from the
                                                                                all!) Their bodies                                                                                                                           excessive heat.
                                                                MELLER'S
                                                                CHAMELEON       are covered with
                 SKIN                                           Chamaeleo       smooth, shiny                                                                                                                                CATCHING
                 has cells                                      melleri         scales.                                                                                                                                      A FEW MORE
                 with many                                                                                                                                                                  COMMON IGUANA                    RAYS
                 pigments.
                                                                                                                                                                                            Iguana sp.                       6:00 PM
          TAIL           PREHENSILE TOES                                                                                                                                                                                     They return to the
          curls up       can surround a branch                                                                                                                                                                               sunlight but elevate
          when           and hold on tight.                                                                                                                                                                                  their bodies to take
          necessary.                                                                                                                                                                                                         advantage of the
                                                                                                                                                                                                                             heat radiating from
                                                                                                                                                                                                                             the rocks.

                                                                                                                                                                                                 Iguanas
                                                                                                                                                                                                 Iguanas belong to the largest New World group of reptiles and
                                                                                                                                                                                                 have the most complex design. They inhabit tropical regions of
                                                                                                                                                                                                 the Americas, including the forests of Mexico. They can change
                                                                                                                                                                  FEET WITH                      color during mating season. The species of this group are
                                                                                                                                                                  CLAWS                          vegetarians.
                                                                                                                                                                  enable it to walk,
                                                                                                                                                                  climb, and dig
                                                                                                                                                                  burrows.
             CLAW
   45   46   47   48   49   50   51   52   53   54   55