I’m Sensing a Pattern


How does a dolphin save you from a shark?

There are several stories from all over the world about dolphins “saving” people from shark attacks.  Stories include dolphins forming a protective ring around the person endangered, tail slapping the water, or chasing the shark away.  But, sharks are a very real threat to dolphins, so they need to make sure that they are safe too. 


How does a dolphin save people when they can’t hear underwater?  

Everyone should remember that dolphins are not there to act as lifeguards for human swimmers!  But, since they have been reported to “save” humans, how do they communicate danger?  There are many ways that a dolphin can alert humans and much of it requires observation.  A swimmer in danger can look for visual cues from the dolphins, such as erratic swimming.  A dolphin  may even use physical contact, although this is rare. 

Also, humans can indeed hear under water.  However, because our ears were designed to hear sounds in the air, under water we cannot tell where a sound is coming from.  Instead you hear the sound from all around.  This is because sound travels 4.5 times faster in water then in air.  Luckily for the dolphins, they can hear perfectly under water!

What do dolphins like to eat?

What dolphins eat depends on the kind of dolphin, and where they live.  Killer whales, the largest of the dolphins, eat anything from seals to salmon to squid.  Bottlenose dolphins will eat a variety of fish, crustaceans, and small squid.  Here in Bimini we observe bottlenose dolphins crater feeding on gobies and garden eels.  When a dolphin crater feeds, it swims along the sand, using its echolocation to find prey buried in the sand.  Atlantic spotted dolphins feed on fish such as mackerel, gobies and ballyhoo as well as cephalopods. 

 Why are dolphins so sweet?

Dolphins are actually what we consider to be “complete social animals,” just like chimpanzees and people. This means that while the behavior we may see most often on a TV program is playful frolicking, they are capable of aggression. Different individuals may be more aggressive than others, some individuals may be more inquisitive, some may be more playful – the list goes on.


How does a dolphin protect its body?

Dolphins have lived on this earth for a very long time and have evolved very well to meet all the requirements necessary to survive in the ocean. They have many different adaptations that they combine to protect themselves from natural predators such as sharks. 


Dolphins almost always travel in groups, so they have safety in numbers.  Their echolocation allows dolphins to “see” predators from a long distance away, so they can better avoid them. Many dolphin species have coloration patterns that act as a camouflage to make it difficult for predators to see them. If a dolphin cannot completely avoid a predator, their streamlined bodies and powerful tails that allow them to swim very fast. Finally, dolphins may ram a predator with their very hard rostrum, bite back with their powerful jaws, or hit the predator with their strong tail fins.


 If they are mammals, where is their hair?

As you may know, dolphins are mammals. One of the defining characteristics of all mammal species is that they have hair on their bodies. But, what about dolphins? With their smooth streamlined shapes, it doesn’t look like they have any hair at all – do dolphins have hair? In fact, when dolphins are born, you can actually find a few stray hairs poking out of their chin. But soon after birth these hairs will fall out and all you will be able to see are hair follicles which are tiny pockmarks that the hair used to grow out of. Some of the larger whales have hair that stays with them their entire lives. Humpback whales have distinctive bumps on their lower and upper jaw from which tiny hairs protrude.  These hairs may actually help humpback whales to sense things in their environment, much like a cat’s whiskers.  Dolphins don’t really need hair to survive: they can keep themselves warm with a toasty layer of fat under their skin (called blubber). Having no hair on their bodies makes it easier for them to swim in water. This is the same reason that Olympic swimmers tend to shave all the hair off of their bodies.  Less hair equals less drag which means an easier time chasing after fish!


 Is there such a thing as a “rogue” dolphin?

Dolphins are very social, so they spend the majority of their time in pods and groups. However, that doesn’t mean that they aren’t capable of breaking away from the group and swimming by themselves for a little bit. Very rarely a dolphin seems to completely cut itself off from the rest of its group and may spend most of time closer to humans and boats.  These animals are called “lone social dolphins” and have popped up in various places all over the world.