Dolphin Travel Ranges

Our crew has an absolutely fantastic job monitoring the local dolphin behavior. The daily routine of documenting the goings on of our population never gets old and the opportunity to share this information with guests on board our boat is just as rewarding. Every excursion is just a little different and with nearly 18 years of data, discovering new things about our dolphins is becoming more consistent. 

Environments change, habitats and food sources may differ so some of the bottlenose populations will travel and migrate more than others. Let’s take a look at how a few will differ.

Offshore, in deeper waters bottlenose dolphins may form groups of 100 or more for two reasons. First, there are larger predators in deep waters so safety in numbers will justify a larger group or “pod.” Next, food is more spread out so feeding in larger groups when a pod comes across a very large school of fish, the numbers are in their favor to catch more food. As a general rule, the deeper the waters, the larger the pods.

Coastal dolphins are usually found in much smaller groups of 20 or less. Near the shorelines, in the bays, estuaries, rivers and canals there is no need for larger groups to feed together because there is just not enough depth in the water for them to work cohesively. Also, shallower waters mean smaller predators. There is not a food source for large sharks in the backwaters, bays and estuaries. They are here, but not very large.

The distribution and migration of food for dolphins, primarily fish species, can be attributed to the seasonal changes in water temperatures and could easily help us understand the movement of dolphins in those areas. Coastal and inshore dolphins that are located in shallow, warmer waters exhibit less extensive travel ranges than those in colder waters. As fish move to warmer waters for the winter, dolphins will follow and some Atlantic dolphins will move from the New England coast all the way to the Carolina waters.

Coastal bottlenose dolphins have the best of both worlds. The waters are warmer so many fish are found all year long here. If food is plentiful, there is no reason to stray far from your birth area and leave other dolphins that have formed social bonds with the subject… unless you are an adult male.

The coastal adult males may travel more extensively than females and younger dolphins for the purpose of finding females to mate with. They can range among several societies of dolphins for that reason, resulting in a larger travel range.

Coastal dolphins in shallow, warm waters exhibit a more localized movement throughout the entire year. These dolphins have a home range and are considered “local residents.” This is the societal behavior we document around Marco Island. Local resident behavior has been recorded along the coasts of Georgia, Texas, Southern California, Gulf of California, South Africa and here in Florida.

Females with calves by their sides will sometimes create a smaller, local “zone” to teach their calves where to feed and how to feed. This is called a “Natal Range.” So, when a calf is old enough to leave mom’s side, it knows where to feed.

So the travel range of our local residents is limited but as mentioned above, there are always surprises as we conduct our survey work. Recently, our Marine Biologist, James, was paddle boarding with his family close to Naples Pier. He noticed two dolphin moms and calves, side by side, and was able to identify them by markings on their dorsal fins, the fin on the back you see when a dolphin surfaces for air. One mom is named Rakes and she was traveling with her 14-month-old calf Pitchfork. The other mom, MT2, was traveling with her 3-month-old calf Spirit.

Rakes and MT2 are often seen in our north Marco area, near Big Marco Pass and the surrounding sand bars. Naples Pier, as the crow flies, is about 10 miles north of their normal sighting area. This is new to us, seeing a mom with a 3-month-old traveling that far from their regular feeding area…and they were still moving north! This opened our eyes, and our minds, to the fact that moms with calves have a much more extensive travel range than we thought!

In summary, dolphins in deeper waters and seasonally cooler climates will migrate much further due to movement of their food supply. Our coastal bottlenose dolphins stay here all year long since food is plentiful and predators are smaller, and their travel range is far less than the deep-water relatives.

However, we are always ready for those surprises, like the recent range of Rakes and MT2 and their calves, and any other findings that we can document and help us more fully understand these amazing cetaceans that call Marco Island home. Stay tuned!