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          A key definition of an animal, as opposed
        
        
          to a plant, is that most animals can move
        
        
          voluntarily. Animals must also eat other living
        
        
          things to survive. Let’s take a look at some of
        
        
          the things animals do.
        
        
          What is an animal?
        
        
          
            Food is fuel
          
        
        
          All animals have to find
        
        
          and eat food to survive.
        
        
          Carnivores are animals that
        
        
          eat meat. Herbivores eat
        
        
          mainly plants. Omnivores
        
        
          are creatures that eat
        
        
          both plants and meat.
        
        
          
            What a nerve!
          
        
        
          Animals have
        
        
          nerves, which carry
        
        
          information from their
        
        
          sense organs. Most
        
        
          animals have
        
        
          brains to
        
        
          monitor this
        
        
          information. The
        
        
          nerves also carry
        
        
          orders from the
        
        
          brain to the organs
        
        
          and muscles – such as
        
        
          instructions to stay still,
        
        
          attack, or run away!
        
        
          How many species of animal are there on Earth?
        
        
          
            The living world
          
        
        
          Squirrels eat seeds,
        
        
          nuts, fruit, and fungi.
        
        
          
            Bald eagle
          
        
        
          
            Swimming:
          
        
        
          animals
        
        
          like fish swim by moving
        
        
          their bodies and fins.
        
        
          
            Slithering:
          
        
        
          some snakes
        
        
          wriggle, others raise and
        
        
          flatten their bodies.
        
        
          
            Reaching:
          
        
        
          sea anemones
        
        
          reach out their tentacles
        
        
          to sting prey.
        
        
          
            Walking and running:
          
        
        
          many animals walk and
        
        
          run using legs.
        
        
          
            Flying:
          
        
        
          birds fly by
        
        
          flapping wings or gliding
        
        
          on currents of hot air.
        
        
          
            Getting around
          
        
        
          Many animals have
        
        
          muscles, which allow
        
        
          them to move in a
        
        
          variety of ways.