Along the Nile River in Africa, fierce crocodiles make their home. Feared by man and beast, their powerful jaws are lined with rows of sharp, white teeth. However, a small bird called the Egyptian plover, or crocodile bird, walks safely among them. The plover is the crocodile’s dentist.
When the crocodile opens its jaws, the bird hops into the huge mouth, acting as a feathered toothbrush. This dainty bird walks safely up and down the rows of teeth, cleaning out particles of food. The patient crocodile waits for the dental work to be completed before closing its jaws. When finished, the crocodile bird has a full stomach, and the crocodile has free dental care.
After the dental work is done, the plover often jumps on the crocodile’s back for a free ride. In return, it lets out a loud chirp if danger is near.
The crocodile and the Egyptian plover practice symbiosis, a Greek word that means “life together.” Their particular kind of symbiosis is called mutualism, which means that each partner gains an advantage from the teamwork. Though very different, they help each other live more comfortably.
Symbiosis can also be found in the sea. Many hermit crabs set up housekeeping with sea anemones. The hermit crab finds an empty shell, then seeks a sea anemone to live on the shell. The sea anemone’s stinging tentacles protect the hermit crab, and the crab’s leftovers provide food for its house guest. If the crab outgrows its shell and moves to a bigger one, it urges its anemone to move to the new quarters.
Symbiosis can also turn animals into farmers. Some ants raise plant aphids, a small insect, much as dairy farmers raise cows.
By stroking an aphid’s back with its antennae, an ant “milks” it for a liquid called honeydew, which is one of the ants’ favorite foods. In return, the aphids are protected and given food and shelter.
Some animals cooperate to obtain food. The ratel, a member of the weasel family, and the honey guide, a small bird belonging to the woodpecker family, often combine their efforts to get a meal.
The honey guide loves beeswax and bee grubs above all else. It can easily find the nesting place of the wild bees, but its bill is too small to break open the hive. The ratel, or honey badger, loves honey but can’t find hives as well as the honey guide, so when the fluttering, chattering bird appears to show the way, the ratel happily follows. With sharp claws and teeth, it opens the hive and eats the honey. Meanwhile, the honey guide is patient. It knows that the ratel and the bees will soon be gone and that there will be plenty of grubs and beeswax left. Many African tribes also follow the honey guide. Since they believe that the bird will not show them locations if it doesn’t receive its share, they are happy to leave the grubs and beeswax. This is man and bird practicing symbiosis. Can you think of other animals that are symbiotic with man?