For animals in the wild, each day is a struggle to survive. They must
continually search for food, while at the same time keeping themselves
safe from predators. Some animals have learned that teaming up with
another animal makes the struggle to fi nd food, shelter, and safety a bit
easier. This kind of special relationship in which animals depend upon and
benefi t from one another is called symbiosis.
One of the most visually surprising examples of symbiosis occurs between
the fearsome African crocodile and the small plover bird. When a plover is
nearby, a crocodile will open its long, sharp-toothed jaws to invite it inside.
You might assume that the plover would quickly reject this invitation
and fl y off . Yet surprisingly, the plover does hop inside. Perhaps even
more amazingly, the crocodile, normally known for its aggression, does not snap its mouth shut and have the plover
for a snack. Instead, it remains still, not closing its mouth until the plover leaves. How can this strange behavior be
explained? The answer is symbiosis. The plover picks out all the small pieces of meat stuck between the crocodile’s
teeth. In doing so, it cleans the crocodile’s teeth, which prevents it from getting infections. Because the crocodile can
not clean its own teeth, it depends on the plover to perform this service. In return, the crocodile provides an easy
meal for the plover.
In some cases of symbiosis, like the crocodile and the plover, each animal in the pair benefi ts from their relationship
in a different way. However, in other cases, the animals share a common goal. This is true of the honeyguide bird and
the ratel, a furry creature with short legs and long claws. Both these animals live on grasslands in Africa and have
an appetite for honey. As its name suggests, the honeyguide has a special ability for locating beehives. However,
this small bird cannot open a beehive to get at the honey. To accomplish this, it teams up with the ratel. Ratels are a
perfect match for the honeyguide as they love honey, are large enough to crack open a hive, but have no ability to
fi nd hives themselves. The honeyguide fl ies over grasslands looking for
a hive. When it does spot a hive, it swoops down and makes a noise to
alert the ratel. The ratel uses its claws to tear open the hive. After eating
its fi ll, the ratel invites the honeyguide to fi nish the leftovers.
Another two animals that team up to compensate for their own
weaknesses are the zebra and the ostrich. These two animals often
travel together. This is no surprise since they are a perfect match. While
the giant, fl ightless ostrich has poor senses of both smell and hearing,
the zebra has acute senses of smell and hearing. On the other hand,
the zebra has terrible eyesight, while the ostrich has excellent eyesight,
enhanced by its long neck which enables the ostrich to see far into
the distance. In this way, each makes up for the other’s defi ciencies. As a result, the animals are far safer together than
they would be apart. Ostriches can see predators, such as lions, far in the distance, while zebras can smell or hear
others as they approach.
Birds and land animals aren’t the only ones that work in symbiotic pairs. Some sea animals, like the clownfi sh and
the sea anemone, do as well. Sea anemones, which look like plants, are actually dangerous animals with poisonoustentacles. Most fish stay away from anemones to avoid being stung. However, the
clownfish makes its home among the sea anemones. It does not get stung because
its body is protected by a special coating. Living among the deadly tentacles of an
anemone has a clear advantage—most predators stay away! Another benefit for the
clownfish is that it is able to eat the anemone’s leftover bits of food. But what is the
advantage to the anemone? There are several. First, the brightly colored clownfish
attracts predators. When the clownfish swims under the anemone’s tentacles to
safety, if the predator follows, the anemone has the chance to sting and eat it. Other
services the clownfish performs are cleaning up food scraps and dead anemone
tentacles, and chasing away fish that might eat the anemone.
While many symbiotic pairs may at first look like odd partners, the benefits they provide one another are invaluable,
and may make the difference between life and death. In fact, it is often these animals’ very differences that make
them perfect partners.