On July 20, 2013, a long-term resident dolphin of Sarasota Bay, known as”Otter,” succumbed to complications from a series of wounds probably caused by boat propellers. A 37-year-old male, he had been observed on more than 800 occasions by SDRP scientists since 1980.
“The loss of Otter from the local Sarasota Bay dolphin community, especially in such a horrible and unnecessary way, has hit all of the members of our research team very hard.”
His injuries occurred between the time he was observed uninjured on July 9, 2013 and when his injuries were first observed on July 15, 2013. He subsequently attempted to strand on July 17th, but prior to the arrival of rescue personnel from Mote Marine Laboratory’s Stranding Investigations Program, he moved away and was observed offshore. There were no more reports of Otter until his carcass was reported on July 20th. Upon necropsy (animal autopsy), it was found that he had acquired several additional apparent propeller cuts on his peduncle (tail stock) since the first observation of his injury.
Otter was instrumental in teaching scientists about one of the most fascinating aspects of bottlenose dolphin social structure – the male pair bond. Over the course of their lifetime, about 90% of adult males will form a strong bond, or alliance, with another male, often of similar age. These males will remain together for many years, often until one dies.
The concept of dolphin alliances between “wingmen” was first discovered with Sarasota Bay dolphins, and it has since has been described from other dolphin populations around the world.
Otter was one of the first to show scientists how the bonding progressed over time. When he was approaching sexual maturity, at about 9 years of age, he began to spend most of his time with an 8-yr-old male, known as “Racing Stripe.” These two males swam together as alliance buddies for the next two decades, until Racing Stripe disappeared in 2005.
In recent years, Otter had formed a new pair bond, with a male known as “Petey” who was five years younger. Scientists believe that dolphin wingmen improve chances for mating success, by working together to keep other males away from receptive females. If this is the case, then Otter should be considered a successful wingman, helping to leave quite a legacy. Paternity tests show that he may have sired one calf himself, Racing Stripe sired 3-4 calves, and Petey sired 2 more calves while with Otter. The dolphin buddies may also benefit each other by providing protection, and helping to capture prey fish.
Petey was with Otter when a SDRP dolphin survey crew first observed the injury. At the time, Otter seemed to be swimming, breathing, and behaving normally, giving scientists some slight hope that he might be able to recover from his grievous wounds.
Says Dr. Randall Wells, director of the SDRP, “Over the decades we have seen some dolphins recover from bad boat strikes, but never from one this severe. Many people believe that dolphins are too nimble to get struck by boats, but 5% of our resident dolphins have the scars from boat strikes. I hope Otter can serve as an example to encourage members of the boating public to slow down when they are around wildlife, especially in shallow waters where dolphins, manatees, and turtles can not dive to safe depths. The loss of Otter from the local Sarasota Bay dolphin community, especially in such a horrible and unnecessary way, has hit all of the members of our research team very hard.”
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