A Date with Dolphins
"GOTTA MINUTE, SIR?"
D. Glootnoot the journalist is standing at the edge of the quay and shouting as loudly as she can. Around her, a couple of grinning fishermen stop to watch the show. The man whose attention Glootnoot's trying to get is on a boat, and the boat is just about to set off. Glootnoot is determined to be aboard when it does.
Finally hearing her, Rahul Nolan, noted Dolphin researcher looks down and waves. "SURE!" he shouts back, "WANT TO COME ABOARD?" Glootnoot nods vigorously. Moments later, a gang plank is lowered and Glootnoot clambers aboard. Within moments they are slowly chugging out of the harbour, heading out into the ocean in search of dolphins.
Glootnoot stands with Mr. Nolan at the rail, watching the little white waves the boat leaves in its wake.
Nolan: It's easy to think of dolphins as fish… after all they live in the sea. But dolphins are actually mammals. They are warm blooded like man, and give birth to one baby called a calf at a time.
Glootnoot: I've heard that dolphins have plenty of other things in common with man as well. Is that true?
N: Yes. Dolphins love to spend time together, moving in groups called pods. On average, a pod may have 12 dolphins, but sometimes where there is lots of food many dolphin pods get together temporarily and form a superpod. Such groups may have more than a thousand dolphins! Can you imagine that?
Glootnoot can't; but she thinks it must be a simply amazing sight. More than a thousand dolphins! Nolan explains that within a pod, some dolphins even seem to have special friends. He says that you can see dolphin buddies swimming along face to face and touching flippers.
N: They're also very playful… and will spend hours trailing boats and leaping into the air.
G: I've seen dolphins do that on T.V! It's really cool!
N: They're pretty inventive. For toys they use seaweed and anything else that floats. They love to play-fight with other dolphins, and will even harass other locals, like seabirds and turtles.
It turns out that that dolphins also leap out of the water to herd fish – like cowboys on horses, they surround the fish, make a lot of noise and force their food to go in a certain direction. Glootnoot loves to swim herself, and so she knows that jumping out of the water like that is a lot tougher then it looks. Nolan explains that dolphins use their powerful tail flukes in an up and down motion to move through the water.
N: Dolphins also use their tails when hunting, using it to hit a fish that is trying to escape. A dolphin may actually hit so hard that the fish flies up into the air and is stunned by the time it falls back into the water.
Nolan shows Glootnoot a picture of a dolphin. In the picture the dolphin looks like it's grinning. Glootnoot can't help but grin back… she thinks they're adorable. Pointing to the little, sharp, conical teeth of the dolphin, Nolan explains that they're perfect for holding onto slippery fish. Apparently, dolphins don't bother with boring things like chewing – they eat their fish whole, head first.
G: How do they find their fish? Do they have great eye sight?
N: They use something called echolocation to find fish. A dolphin sends out a stream of clicks. These 'clicks' are pulses of ultrasonic sound and dolphins may repeat this sound as rapidly as 800 times a second! When these outgoing sound waves or 'clicks' bounce off objects in their path, a portion of the signal is reflected back to the dolphin, and the dolphin knows where its food is.
G: That's amazing, but I thought that was the way they spoke to each other!
N: They do that too. They whistle or even use body language to communicate. When a baby is first born, a mother dolphin will whistle to it constantly, 'imprinting' her sound on the baby so it will recognize her.
G: Does the baby whistle back?
N: In time a baby learns to develop its own signature whistle. Some researchers believe that each dolphin has its own individual signature whistle, just like a name.
G: Dolphins look so friendly.
N: Many are. But you had better watch out if you see a dolphin slapping its tail on the water. This may be a sign of annoyance, or a warning to other dolphins of danger. In the wild a dolphin will open the mouth as a sign of aggression, and even nod its head. But you know a dolphin is really frothing mad when it begins to 'clap' its jaw.
G: I'll keep that in mind. How do dolphins breathe? Do they have gills like other fish?
N: No. Dolphins actually breathe through a 'blowhole' located at the top of their head. Kinda like whales. They do this pretty fast though… a dolphin may empty and refill its lungs in less than a fifth of a second. As the dolphin breathes the air leaves the blowhole at amazing speeds – often over 100mph.
G: How do they keep their blowhole from filling up with water when they sleep? Come to think of it, how do they sleep?
N: Dolphins actually control their breathing – unlike you or I – they choose when to breathe. To sleep, a dolphin actually shuts down only half of its brain, so that it can keep breathing with the other half. They take short little naps, floating just below the surface, and then slowly rising to breathe.
G: What if they're sick and can't come to the surface?
N: If another dolphin is drowning, other dolphins will come to its aid, supporting it with their bodies so its blowhole is above the water allowing it to breathe.
Glootnoot is rather impressed. But then she's heard that dolphins were always the friendly sort.This doesn't stop them from getting killed however. Man isn't as nice to dolphins as he should be – a lot of them are killed for food, but also indirectly in nets and because of pollution.