Capt. Cathy Eagle
Bottlenose dolphins have a number of unique hunting techniques that are dependent on the dolphins’ location. One technique is called "sponging". This is when the dolphin places a sponge on its beak to protect it from sharp rocks and coral while digging for fish on the seabed. It protects their rostrums or beaks.
This behavior is a learned skill passed down from mother to offspring. It is quite comical to observe the dolphin with a sponge on its head. Dolphin in disguise. Perfect for Halloween!
Dolphins have many fishing strategies but when sponge is available, bottlenose dolphins use this unique hunting technique. We don’t have sponge readily available in Southwest Florida because sponges need a hard surface to attach to and grow.
It is a popular fishing technique in the Florida Keys and in Tarpon Springs, a city just north of us on the Gulf Coast of West Central Florida.
The city of Tarpon Springs was actually founded by Greek sponge divers in the early 1900s, and their tradition continues today, with local Sponge Docks still active.
The sponging technique is a complex behavior that is both time-consuming and a difficult task to master. It is passed down from the mother since adult male dolphins do not participate in raising or teaching their calves.
Sponging can be dangerous at times because the sponge covers the melon head of the dolphin and interferes with the dolphin’s echolocation.
The sponge acts like a glove over the dolphin’s melon. Echolocation originates from the melon on the head. The melon is used to navigate and hunt by producing high-frequency clicks that bounce off objects, creating a detailed “acoustic map” of the dolphin’s surroundings.
Dolphins receive the echoes in their lower jaw and then the information is transmitted to the brain to determine an object’s location, size, shape, and speed. They are able to “see” with sound.
Sponging is a female-dominated hunting technique. The sponging technique is also a social behavior, and sponging females tend to associate more with other spongers. A calf will observe its mother sponging for several years to learn the skill.
The discovery of sponging was the first published instance of tool use among dolphins. The behavior has been traced back to approximately 180 years ago, to a single female who has been nicknamed “Sponging Eve”.
Capt. Cathy Eagle
Capt. Cathy's Boat Tours
Matlacha, Florida
(239) 994-2572
www.CaptainCathy.com
