Jaws open, a tiger shark springs forward. It sinks its razor-sharp teeth into a giant manta ray’s fin. T e ray rears up. A red cloud of blood oozes from it. With the taste of blood in its mouth, the


shark lunges forward again. It misses as the ray twists out of reach and speeds away. Bleeding, the ray begins a long journey.


It swims along the coast of Africa, looking for food and help. Two days later, it swims into a coral reef.


It heads to the top of the reef where it settles down, resting. Spotting the ray, small groups of fish swim out of their hiding places. T ey circle, then swarm around the ray. T is is the help the ray has been looking for. T ey’re “cleaner fish.” T e cleaner fish go to work. One kind eats


parasites clinging to the ray’s belly. Another kind eats algae that have built up around the ray’s mouth. A third kind cleans out the ray’s bite wound. Aſt er a few hours, the fish are done and


the ray is ready to move on. It swims away from the reef, back into deeper water. T e cleaner fish and the ray help each


other. T e fish get a good meal and the ray gets clean. T is is an example of mutualism. Mutualism happens when two living things need each other.


spotted stingaree


Flat Sharks Mantas are only one kind of ray. More than 500 ray species swim in the ocean. Rays are fish, closely related to sharks. T ink of a ray as a fl at shark, minus the


sharp teeth. Some kinds have a body shaped like an oval. Others have a body shaped like a diamond. T en there’s the guitar ray. It really is shaped like a guitar. Diff erent rays grow to diff erent sizes. Some


could sit in the palm of your hand. Others are larger than four cars parked side by side. T e short-nose electric ray is the size of a pancake. T e manta is much larger. It weighs as much as an elephant.


Flapping Fins No matter its shape or size, all rays have a tail and fins on theirs sides. T ese fins are called pectoral fins. T ey almost look like wings. T e cownose ray fl aps its pectoral fins up and down like a bird. It is in constant motion. It dips and climbs, rarely resting on the seafl oor. Another kind of ray swims along the


seafl oor. It’s the spotted stingaree. Its fins ripple from front to back. T is motion pushes the ray forward. It also lets the ray hover over prey. A ray uses its f ins and tail together to help it


move through the ocean. During a fight, a tail can also be a weapon. Take the blue-spotted stingray, for example. It has sharp barbs on its tail. Each barb holds poison. In a fight, the stingray cracks its tail like a whip. It stings its attacker.


A ray has to be careful. It doesn’t have a hard shell to protect itself. It doesn’t even have bones. Instead, it has a skeleton made of cartilage. Cartilage is tough and it stretches a little. Still, it’s not as strong as bone.


To see what cartilage is like, wiggle your nose with your fingers. Cartilage forms the tip of your nose.


20 NATIONAL GEOGRAPHIC EXPLORER


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