Common bottlenose dolphins (Tursiops truncatus) are an adaptable species that live in coastal and oceanic environments throughout much of the world. They are the only species of cetacean native to Texas bays and estuaries and the only ones you will see within Galveston Bay. They are long lived mammals, potentially living over 50 years and raising several generations of offspring, while depending on the rich resources of our Bay. Their health and ability to thrive here can provide a wealth of information about the ecosystem we share with them.
Researchers identify dolphins using nicks and notches in their dorsal fins that create a unique pattern, allowing individuals to be identified and tracked over time. These markings are usually created naturally, though sometimes may be the result of interactions with boats, fishing gear or even sharks. GDRP has identified over 700 unique individuals spending time within the inshore waters of Galveston Bay.
Meet the Dolphins
Get to know some of the dolphins living in Galveston Bay
What do dolphins do all day in Galveston Bay? Dolphins engage in a variety of natural behaviors and interact with human activities. They move around the Bay, spending much of their day traveling from place to place. Below are a few other behaviors that researchers see while studying dolphins in our Bay. If you see dolphins in Galveston Bay and surrounding waters, you can report your sighting here!
Dolphins are often found where the fish are! While most feeding takes place under the water and is hard to see, sometimes dolphins engage in “fish tossing” or will bring a fish to the surface in their mouth where our researchers will catch a glimpse of it. Other behaviors that may indicate dolphins are feeding include “swirling” at the surface and long “fluke-out” dives.
Dolphins are social animals. They often maintain social bonds within a community through tactile behavior. These interactions are usually friendly, but may also be aggressive. Socializing dolphin groups may roll, splash and leap in the air. Maybe unsurprisingly, similar to humans, groups of juvenile dolphins tend to be the most rowdy!
It is always exciting to see dolphins leap out of the water with their entire body. Dolphins may leap to communicate with each other, to remove remora fish attached to their skin, when they are traveling fast, when they are riding boat wakes, or when they are socializing with other dolphins.
Sometimes dolphins forcefully slap their tails on the surface of the water making a booming noise. This behavior is a form of communication, and sometimes may indicate aggression or irritation. While it is commonly performed ‘dorsal-side-up’, dolphins in Galveston Bay often like to do this ‘belly-side-up’.
Dolphins commonly ride on the pressure wake created on the bow of ships, barges and other vessels. While there may be an energetic benefit to traveling the Bay in this manner, dolphins most likely engage in this activity because it is fun! Recreational boaters should not seek to engage this behavior, but if dolphins appear on your bow, maintain speed and heading when possible, avoiding abrupt movements.
Dolphins often follow closely behind active shrimp trawlers in Galveston Bay. This behavior is likely a strategy to get an ‘easy’ meal, feeding on trapped, weak or dead fish and shrimp. Interactions such as these could increase risk of injury from gear entanglement and dependence on human activity for food.
Researchers in Galveston Bay have noticed a worrisome behavior when dolphins are feeding behind shrimp trawlers. Dolphins will lift the trawl lines either with their rostrum or with their head, just behind the blowhole. While these interactions tend to be brief, we have noticed scars on some dolphins potentially caused by this risky behavior.
Begging and Depredation
Unfortunately, dolphins sometimes learn to obtain food directly from humans. They may scavenge discarded fish, take catch from lines and traps and even beg from humans who illegally feed them. These interactions can be harmful to dolphin health. Keep dolphins safe by following safe boating and fishing guidelines and never feed wild dolphins!