Q. What types of dolphins live around Bimini?
A. There are two different species of dolphins here in Bimini. Most often, we see Atlantic spotted dolphins. Their scientific (Latin) name is Stenella frontalis and these dolphins are approximately 6 feet long and weigh about 250 pounds. We also see bottlenose dolphins (Tursiops truncatus). They are slightly larger (about 8 feet, 400 pounds). There are thought to be two "ecotypes" of bottlenose dolphins, inshore (or coastal) and offshore (or oceanic). In Bimini, we regularly see coastal bottlenose dolphins.

Q. How do you recognize individual dolphins?
A. This depends on which dolphin species we are looking at. Atlantic spotted dolphins are mainly recognized by their spot patterns. Spot patterns are unique to each individual, but the pattern changes over time as the dolphins develop more and more spots. Sometimes, we also use nicks and scars on the dolphin's body to tell it apart from other dolphins. Bottlenose dolphins are recognized by the shape of their dorsal fin, as well as any nicks that might be present.

Q. How many dolphins live near Bimini?
A. As of August 2009, Dolphin Communication Project researchers have documented 91 individual spotted dolphins and 37 bottlenose dolphins. Accounting for calves (who all look the same!), deaths and the possible dolphin that doesn't come by our cameras, we estimate the Bimini Atlantic spotted dolphin population to be stable at approximately 120 individuals. We still have a lot to learn about the bottlenose dolphins, so we aren't sure how many of them visit Bimini.

Q. How do you tell how old a dolphin is?
A.There are only two ways to know for sure how old a dolphin is: watch its birth or pull its tooth. Dolphins' teeth have rings inside — similar to a tree trunk. But, since we don't get to witness dolphin births and we can't pull their teeth, we estimate their ages. Spotted dolphins are born without spots and they develop more and more spots the older they get. Bottlenose dolphins are a bit trickier. We compare their size to an adult; a calf is about 1/4 of an adult's length, a juvenile is 1/2 and a sub-adult is 3/4.

Q. How long do dolphins live?
A. This answer depends on the dolphin. The general rule of thumb is that the larger a dolphin is, the longer it lives. So, what is the largest dolphin? The orca or killer whale. Killer whales can live to be 80-90, even 100 years! Bottlenose dolphins are much smaller and may have a lifespan somewhere between 40-60 years. Since the spotted dolphins are slightly smaller than bottlenose dolphins, we expect their lifespan to be a bit shorter. We'll have to wait and see what we learn here in Bimini!

Q. What types of predators and threats do dolphins face?
A.The only natural predator to Bimini's dolphins is sharks. It is rare for us to see dolphins interacting with predatory sharks; when they are swimming with us, they are relaxed and generally in play/social mode. The other threat to dolphins is humans — too much boat traffic and noise, pollution and improperly discarded fishing line. Boats should always be operated carefully when in close proximity to dolphins, multiple boats should not crowd dolphin groups and garbage should always be taken back to shore and disposed of properly.

For more dolphin FAQs, visit the Dolphin Communication Project's FAQ page.