Learning to listen to dolphins
It's not easy eavesdropping on a dolphin.
Marine mammal biologist Frants Jensen spent all Wednesday searching for dolphin chitchat.
The ocean was rough, there was a torrential downpour and no sign of dolphins.
“We probably travelled 90 miles,” said the 34-year-old dolphin and whale communications expert. “We'll try again tomorrow if the weather holds.”
The next day they had better luck.
“I am here with about eight researchers and a handful of PhD students,” said Dr Jensen. “Our main objective is to learn more about bottlenose dolphins living off Bermuda.”
The researchers are here as part of the Bermuda Wild Dolphin Project, a collaboration between several scientific institutions including the Bermuda Aquarium, Museum and Zoo, Texas A & M Corpus Christi, the Chicago Zoological Society's Sarasota Dolphin Research Programme, the Woods Hole Oceanographic Institution and Dolphin Quest Bermuda. The project aims to increase knowledge of Bermuda's dolphins.
Dr Jensen has worked at Woods Hole Oceanographic Institution and at Princeton University and is now a junior fellow at the Aarhus Institute of Advanced Studies in Aarhus, Denmark. He is an expert in biosonar, basically seeing with sound. Dolphins use a series of clicks and echoes called echolocation to probe their environment.
“Dolphins have a big suite of communication sounds,” he said. “In addition to the clicks, they also have a series of different whistles for social communication.”
When he tells people he researches whales and dolphins, they often imagine him in the water all day long.
“I probably spend three or four weeks out in the field,” he said. “The rest of the time I spend processing data in my office.”
In fact, even when he's in the field, on the ocean, he seldom gets wet.
When dolphins are found, Dr Jensen attaches an acoustic tag to the dolphin using suction cups and long handheld poles.
The tag records the sounds dolphins make, and information about their depth and movement.
The downside to his work is that the equipment is very expensive.
“You can track the tags using an very high frequency (VHF) antennae,” he said.
But sometimes the tags go missing.
“That's what a very bad day at the office looks like to me,” he said. “Once we lose touch with a tag for more than a week our odds of finding it again goes down since the radio runs out of power.
“Once, we actually had a woman find a tag and put it in her car. She forgot about it for two weeks and then contacted us. That was a good day.”
Dr Jensen first saw dolphins as a teenager on a family vacation in the Galapagos Islands. He was entranced.
“I love when they are bow riding in front of you and diving through the water,” he said. “It really illustrates how agile and graceful they are.”
He became interested in echolocation while studying biology in university.
“I was looking for an interesting project to do,” he said. “I had been vaguely interested in marine mammals up to that point, but got excited about echolocation then.
“One of my old professors arranged a research expedition to northern Norway on a sailing boat. He was looking for crew members. I was like ‘this could be an interesting experience'.”
The project looked at sperm whales, one of the biggest echo locating animals in the world.
“The project really solidified my interest,” he said.
This is his first trip to Bermuda. He became involved through work with the Sarasota Dolphin Research programme.
“Their project is the main one trying to figure more where the animals are moving,” he said.
He said Bermuda is an interesting place to study dolphins as the ocean bottom is very steep, and there are nutrient rich upwellings to provide food for dolphins and many other animals.
But he said his was only one of 15 different projects going on during this research venture.
“The acoustic tags only play a small part,” he said.
He will be giving a public talk on Tuesday with another dolphin researcher, Randall Wells, director of the Sarasota Dolphin Research Programme.
Their talk, The Science of Saving Cetaceans, will be at 7.30pm in the Tradewinds Auditorium in the BUEI.
Tickets are $20 for members, $25 for non-members, and $10 for students. Tickets are available by calling 294-0204 or visiting Oceans Gift Shop at BUEI.
To hear a database of whale and dolphin songs, many of them recorded off Bermuda in the 1950s, see cis.whoi.edu/science/B/whalesounds/bestOf.cfm?code=AC2A