What draws us to bottlenose dolphins? Why do we love to see them in the water?
Is it their smarts? Dolphin intelligence is thought by some to be on a par with a child's.
Is it their seeming fun-loving attitude? Their friendliness towards humans? Or is it just that cute dolphin smile?
Whatever the reason, people love bottlenose dolphins.
The Jekyll Island version - the Atlantic dolphin - lives in the nurturing waters along the Jekyll Island coast for much of the year. This is the perfect time to take a dolphin tour and get a good look at these gregarious creatures.
When the water cools in October and November, dolphins head south, following their food source into warmer waters.
They return to the Georgia coast in the spring (it's called the bottlenose dolphin spring break on Jekyll Island!), and may hang out in the same 20 mile area of water each year.
An adult Atlantic dolphin in good health may live up to 45 years.
Dolphin Senses -
Dolphins have good vision in or out of the water. A gland at the corner of each eye secretes mucus and protects the animal's eyes from sea salt.
But they rely mostly on their built-in sonar for orientation and detecting prey. This ability is known as echolocation.
The dolphins generate a clicking noise - up to 1000 clicks per second - which travel through the water. When these sonar waves encounter an object, they bounce back to the dolphin, revealing the object's size, shape and location.
And yes, I did say prey earlier. That cute dolphin is a carnivore, taking food like fish, squid, and silvery eels.
A dolphin's ears are small, not easily seen. They're located just behind the animal's eyes. But they hear well. The animals communicate with one another through a complicated system of squeaks and whistles. They are gregarious and social, even known to come to an injured animal's aid and help it reach the surface.
Dolphins are powerful swimmers, using their fluke to drive them through the water at a cruising speed of 5 to 7 miles-per-hour (mph). They can go faster, maybe 18-22 mph. Some have been clocked at up to 30 mph.
They can also leap, using their flukes to propel themselves out of the water in a breach that might reach 16 feet high.
Bottlenose dolphins also have a dorsal fin. They use it for stability and, maybe, to regulate body temperature and dissipate excess heat. Dolphins are mammals, with a body temperature of 97.7 degrees, close to our 98.6.
Social Interaction -
Although dolphins get along with humans, in their dolphin pods they sometimes fight for dominance. And at times, like humans, they get mad. They might pitch a fit, smacking their tails against the water, showing their teeth, and head-butting rivals.
Sexually, the Atlantic dolphin will mature in 6 to 8 years. Females give birth every 2 to 3 years. They can have as many as 8 babies in a lifetime.
Babies are most commonly born in spring or summer. They're generally from 30" to 36" long, and may weigh up to 20 lbs. They will double their size in 3 to 4 weeks on a diet of rich mama's milk.
Bottlenose dolphins live in family pods of a few males, several females, and their babies. Pods may reach up to 15 individuals. At times, several pods may join together temporarily to form herds of several hundred animals.
Dolphin Size -
How big does a dolphin get? The males grow larger than the females. A teenage male might reach 7-10' long, and weigh in at 300 to 600 lbs.
How Does a Dolphin Sleep? -
Since dolphin's are mammals, they breath air. This poses a problem for the sea-dwelling animals.
Dolphin's breath through a blow hole, located on their backs. Normally they surface every 15 to 20 seconds to breath and clear their blowholes, although they can dive to 600' while holding their breaths for 8 to 10 minutes. They do this by slowing their heart rate and controlling the flow of blood through their bodies.
They might take short naps, lasting several minutes at a time, on the surface. But these little naps are not the only ways dolphins sleep. Scientists using EEG studies have learned that dolphins can let one half of their brains sleep at a time. This way, they can get as much as 8 hours of sleep at a time!
A Bottlenose Dolphin's Diet -
No candy bars for these guys. They start out on a diet of rich mama's milk, and graduate to fish in 3 to 4 months.
They enjoy all kinds of fish and crustaceans, but really like shiny silver fish like menhaden and silver eels. They also love squid and shrimp, and are opportunistic feeders, at times following shrimp boats off the Jekyll Island beaches in hope of an impromptu meal.
A dolphin can eat 12 to 15 lbs. of fish a day. In cold water that will increase to 20 lbs. a day or more.
They're good fishers. In deep water, they will herd a school of fish, circling it and forcing the school to collapse into a tight ball. The animals then take turns darting in and taking a mouthful of fish. They repeat this until all have eaten their fill.
Shallow water fishing is similar in that the dolphins herd their prey, but this time they push a school into very shallow water, sometimes even forcing the fish out of the water onto isolated strand beaches.
They may even follow their prey out of the water, sliding up on the beach on their bellies, snarfing up the fish, and then working their way back into the water.
The sea is a plentiful smorgasbord, and food is usually easily found. And since they live in water, they have all the water they can drink, readily available.
Unfortunately, they can't drink the salt water they live in. They must get their fresh water from other sources.
How? Well, they get some water from the fish they eat. Their kidneys have also adapted to retaining fresh water. And when they metabolize fat, fresh water is a by-product.
Bottlenose dolphins will always be sources of fascination to humans. And who knows? One day, we may learn to communicate with them, and learn a lot more about bottlenose dolphins and dolphin habitat.