Dolphin behaviour experts who visited Cayman this week are warning the public to be alert for warning signs of aggression from the solitary dolphin in local waters.
The experts spent two days in Cayman this week observing the dolphin, nicknamed Stinky, who has been acting sexually aggressively in recent months toward divers, swimmers and boats.
Trevor Spradlin, a marine biologist from the National Oceanic and Atmospheric Administration, said the dolphin was displaying classic, aggressive, dominant male characteristics seen in other lone dolphins and that water users who are educated to spot that kind of behaviour can take themselves out of harm’s way.
“The potential for high-risk interaction is there. We’ve seen it from videos and photos submitted by the public and by the dive operators. There are certain key things that he has done to divers, such as threat displays, he has done open mouth, he’s done chuffs (sharp exhalations of air through the blowhole), he’s done tail slaps... There are certain warning signs that people, if they are educated and if they know the warning signs, can do a lot to minimise what might happen next,” Mr. Spradlin said.
He said a lot of people misunderstand dolphin behaviour. “They think the dolphin, when it opens its mouth, that it’s happy and it’s smiling at them. They don’t realise that's a very aggressive, negative interaction,” he said.
He and his colleague Laura Engleby, along with Chris Dold, vice president of veterinary services at Sea World Parks and Entertainment, all supported the advice that the Cayman Islands Department of Environment has been giving the public about dealing with the dolphin if they encounter him - get out of the water as soon as possible and do not interact with him.
Regarding long-term options, Mr. Spradlin and Mr. Dold said it was not likely that the dolphin could be placed into a pod, as it is not known where the dolphin came from and, besides, pods of bottle nosed dolphins are rarely seen in Cayman. Moving the dolphin into captivity is one possibility, said Mr. Dold, but he added that a “lot of work and observation should happen prior to that to make the most reasonable and best decision for this animal, for his individual welfare”.
Ms Engleby said the team had estimated that the dolphin is about 20 years old, based on his size - a little under 8 feet long - and photographs of his teeth that show they are worn down.
It had been thought he was a young dolphin that had recently reached sexual maturity - hence, reports of his sexual behaviour.
There have been sighting of the dolphin since 2009, but since June this year the sightings have become much more frequent and his behaviour has become increasingly aggressive. Last month, the dolphin held a diver against the sea floor. The encounter was videoed and uploaded to Youtube where hundreds of thousands of people have viewed it.
Ms Engleby said it was typical that as a dolphin becomes more accustomed to humans, his behaviour changes. “The more he gets habituated to human interaction, the more you’ll see that behaviour escalating, which is standard male dominant behaviour that is misdirected towards people. That’s why it’s so important for people to resist the very strong temptation to interact with him because the more that happens, the more those kinds of behaviours are likely to occur and escalate and get more intense,” Ms Engleby explained.
“The more comfortable and habituated they become, the risk increases. The more interactions, the higher the risk,” she added. “That’s why we’re echoing the DoE’s advice for people to try to observe and admire and enjoy from the boat, from the surface,” she added.
The team said there were historically only 30 recorded cases worldwide of solitary male bottle nose dolphin. Ms Engleby is currently studying another lone dolphin in Louisiana.
Cayman’s Department of Environment is going to join a “blue ribbon” panel made up of marine experts to help develop approaches for dealing with solitary dolphins.
In the meantime, the DoE and the experts are urging the public to continue to send videos or photographs of the dolphin to doe@gov.ky.
For more on this story, read Monday’s Caymanian Compass.