Animal partners.
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 form predators. Some animals have learned that teaming up with another animal makes the struggle to find food, shelter, and safety a bit easier. This kind of special relationship in which animals depend upon and benefit 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 reject this invitation and fly 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 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, harmful animals attached to the croc’s teeth. In doing so, it cleans the crocodile’s teeth, which prevents the croc 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.