Wells and a specially trained crew prepare to release a female dolphin following a veterinary exam. Health evaluations are performed on a handful of animals at infrequent intervals. “We much prefer to observe the animals in the wild,” says Wells. “But some crucial information on sex, age, genetics, health, and environmental contaminants can only be obtained through careful hands-on work.” |
He went away to school, but he kept coming back. At the University of California at Santa Cruz, he wrote a Ph.D. dissertation about spinner dolphins in Hawaii and did postdoctorate research on bowhead whales in the Arctic. But three times a year he made his way to Sarasota Bay to follow the bottlenose. In 1982, he teamed up with Irvine and marine biologist Michael Scott to form the Dolphin Biology Research Institute. As his fascination grew, Wells became more and more like a sociologist venturing into a forbidden land, writing down everything he learned about the society he found there. “They’re definitely individuals; they have their own ways of doing things,” he says. “The species’s hallmark is behavioral flexibility.” Rose feeds along the seawall rather than in open water. H lurks under bridges. Blacktip Doubledip always shows a corner of its tail when it dives, in a kind of flippant farewell wave. Pecan Sandie delights in what scientist-observers call “kerplunking,” driving its entire tail—fluke, stock, and barrel—powerfully down into the water, sending up a column of spray. Some of the dolphins enjoy bow-riding—leaping from the water near a boat’s bow wave—and some don’t. Large males tend to be especially slow and stolid, perhaps because they have little to fear or prove. “Some very quickly come up to the boat and some never do, some will look at you and others don’t seem to care,” Wells says. Each individual has its signature whistle. And, like Nicklo, most are readily identifiable by a glimpse of their fins, tails, or bodies. Riptorn’s dorsal fin was left tattered by a boat propeller; Sharkbait has shark-attack scars on its body.
DNA tests made it possible to begin evaluating family relationships, mating systems, and population growth patterns
At first, because so little was known, “we asked broad-based, simpleminded questions,” Wells says. “In the seventies we believed dolphins lived 25 years. Then we found they can live to be 50 and sometimes have calves in their late 40s. We also knew zero at first about dolphin social structure, including who swam with whom and their reproduction patterns in the wild.” As the years passed, Wells recorded more than 17,000 group sightings and conducted as many as 600 observations of specific individuals. “You let the animals tell you what they’re doing,” Wells says. “You can’t go out and manipulate them.”
| Especially abundant in the Gulf of Maine; sometimes seen riding the bow waves of humpback and fin whales |
ROUGH-TOOTHED DOLPHIN | Occasionally sighted amid floating logs in the eastern tropical Pacific; its narrow head and large eyes give it a reptilian appearance |
COMMERSON’S DOLPHIN | Hunted off Chile and Argentina for use as bait in crab fisheries; sticks close to shore and sometimes enters rivers |
COMMON DOLPHIN | Numbers in the millions worldwide; large groups can go into frenzies when feeding, perhaps to panic fish |
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He overcame a major problem in wildlife research—data can be skewed by the human penchant to record only behavior that we find interesting—by recording specific observations every three minutes: where the dolphin is, who it is with, what it is doing. He trained himself to take only physiological data in between, no matter what the dolphin was doing. As technology improved, Wells found ways to use it. He discovered it was easier to see through murky water with a remote-control video camera mounted on a tethered baby blimp. And he added dna tests, which made it possible to begin evaluating family relationships, mating systems, and population growth patterns. “DNA fingerprinting didn’t exist in the seventies,” Wells says. “Now it’s a major part of what we do.” If a calf’s mother is known, taking DNA from the calf and from adult males can disclose who the father was, which can reveal breeding patterns within and between dolphin communities. Wells and his fellow researchers found that Sarasota Bay females, for example, often breed with roving males, including some from Tampa Bay to the north.
Over the years, Irvine and Scott drifted into other career paths—Irvine now designs health-related software in Oregon, and Scott studies various species of dolphins in the eastern Pacific Ocean for the InterAmerican Tropical Tuna Commission. But Wells’s two old friends return for a week or two most summers to help with a bottlenose dolphin roundup. “It’s a social reunion as well as science,” Irvine says. With the help of a couple dozen trained volunteers, Wells and his colleagues remove from six to as many as 30 dolphins from the water for a physical.
The dolphins are encircled in shallow water with a 1,500-foot-long net and then gently lifted, one by one, onto the deck of a boat for a full health assessment. A team of veterinarians records each dolphin’s weight, sex, and blood values. They also perform a diagnostic ultrasound examination and culture blowhole swabs for respiratory-system bacteria. Separate data are taken for specific research projects, including an ongoing study of dolphin communication. Researchers record a dolphin’s voice—its signature whistle—by attaching a suction-cup microphone to the sound-producing “melon” on the animal’s forehead between the beak and blowhole. “Back in the seventies, we were just beginning to recognize the significance and impact of dolphin communication,” Wells says. “Now we’re looking at its effects on population and reproduction patterns.”
A large group of adult dolphins hitches a ride on the pressure wave from the bow of a boat. In open waters, dolphins can effortlessly cruise along at speeds of 18 to 22 mph. |
Some dolphins seem to enjoy the procedure. A few approach the research boat, allow themselves to be hoisted up, then bask on deck, looking around with apparent interest and whistling at others in the water while the team of researchers and volunteers shades the dolphins’ eyes from the sun and splashes cooling water on their skin.
“The bay is a natural laboratory now,” Wells says. “All these dolphins know our boats. They’re tolerant and don’t change their behavior because of our presence.”
The Chicago Zoological Society, based at the Brookfield Zoo, has supported Wells’s work on the bay for the past 10 years. When Wells first forged a relationship with Brookfield, he had the choice of continuing as a single-handed researcher or leveraging his work with help from graduate students who had been exposed to the research literature and field techniques. “I went with the students,” Wells says, kicking off his boat shoes as he settles into a chair in his office. He cranks up his computer and switches on the vhf radio, which connects him to research boats manned by his staffers as well as Earthwatch volunteers and aspiring marine biologists from Woods Hole Oceanographic Institution, the University of California at Santa Cruz, and other universities.
Melon-headed Whale Travels in tight pods of up to 2,000 through the deep waters of the tropics; highly gregarious and combative
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Hourglass Dolphin
An inhabitant of remote Antarctica and subantarctic seas; named for the white patch pattern on its flanks
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Northern Right Whale Dolphin A sleek inhabitant of the North Pacific that lacks a dorsal fin; can travel 22 mph and leap 23 feet
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Long-snouted Spinner Dolphin An agile acrobat of tropical waters; can jump 10 feet in the air, spinning up to seven times in a single leap
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Long-snouted Spinner Dolphin An agile acrobat of tropical waters; can jump 10 feet in the air, spinning up to seven times in a single leap
MELON-HEADED WHALE | Travels in tight pods of up to 2,000 through the deep waters of the tropics; highly gregarious and combative |
HOURGLASS DOLPHIN | An inhabitant of remote Antarctica and subantarctic seas; named for the white patch pattern on its flanks |
NORTHERN RIGHT WHALE DOLPHIN | A sleek inhabitant of the North Pacific that lacks a dorsal fin; can travel 22 mph and leap 23 feet |
LONG-SNOUTED SPINNER DOLPHIN | An agile acrobat of tropical waters; can jump 10 feet in the air, spinning up to seven times in a single leap |
RISSO'S DOLPHIN | Perfers deep, offshore waters; develops a distinctive battel-scarred look from run-ins with other dolphins and squid |
Wells spends a lot of time indoors these days, manipulating computer data and raising grant money. But more manpower has produced better dolphin data faster, and that’s what he cares about. More data continues to produce more mysteries, too, such as the recent discovery that 85 percent of firstborn dolphins don’t survive to become adults. Wells, restless in his bay-view office, can’t wait to find out why. “Nothing is simple with dolphins,” he says. Pollution could be the cause. Toxic runoff accumulates in dolphin tissues over time, and researchers in South Africa have found that when females lactate, they purge most of that accumulation. That means vulnerable firstborns ingest a lifetime of poison with their mothers’ milk. Perhaps it weakens or kills them. Or perhaps new mothers aren’t as wise or as careful as experienced moms are. Under Wells’s supervision, Caryn Owen is investigating the role of maternal experience in calf survival, monitoring how much time mothers spend with their calves and how close they stay together. In Owen’s study, as in almost every dolphin study on the bay nowadays, Wells’s 30 years of data is a crucial foundation. “Caryn can go to the computer, pull up every dolphin’s reproductive history, and tell which ones have had calves and which are likely to be calving,” he says.
Meanwhile, Caryn’s husband, Edward Owen, is probing a mysterious facet of dolphin social life. Detailed observation of the Sarasota population has shown that most males pair off for life with unrelated males, swimming side by side and surfacing to breathe in tandem. One possible explanation is that the dolphins buddy up for protection against sharks. More than a fourth of the dolphins in the bay carry shark-attack scars. Although dolphins don’t sleep, research with captive animals shows that half the dolphin’s brain shuts down periodically, then wakes while the other half dozes. This creates a period of rest in which the animal is probably less alert and could use a friend to keep watch. Or maybe they pair off for protection against other dolphins. Despite the benign image perpetuated by the 1960s tv series Flipper, bottlenose dolphins can be combative. “They’re aggressive,” Wells says. When males reach sexual maturity, they move into adjacent home ranges, such as Tampa Bay, seeking adventure and mates. “We’ve seen violent encounters between males from Tampa Bay versus males from Sarasota Bay, with no females present,” Wells says. “And we know from genetic tests that up to 30 percent of calves are sired by males who are not members of the community. They have battles then too.”
Or there may be an even more surprising explanation for the bonding: The males may pair off in order to gang up on females. One of Wells’s research assistants, Ester Quintana, saw two male dolphins 100 miles north of Sarasota apparently trying to force a female into mating with one of them. “One was under the female and the other was trying to mount her—like a sandwich,” she said. “They tried for 20 minutes.” Wells suspects this may not be an isolated incident. “We see pairs of males isolating a female from the rest of a group and flanking her, a male on each side,” he says. “Sometimes they flank her for hours to weeks, most likely controlling the behavior of other males and keeping them away. With male pairs in captivity doing this, they both get mating opportunities. So maybe this provides better access to females. We’ll do paternity tests and see.”
As Wells’s study gains notoriety with each passing year, more and more graduate students descend on the bay. Stephanie Watwood is analyzing the acoustic patterns of male dolphins to see how they work together. Shawn Noren is studying the respiratory physiology of young dolphins to learn how their diving abilities develop. Anna Sellas is conducting genetic studies of dolphin population structure. Kara Buckstaff is looking into how boat sounds elicit a response from dolphins and how those sounds are affected by sea grass, channels, and the physical environment. Doug Nowacek is observing dolphin foraging behavior.
Like his students, Wells is forever amazed by these enigmatic mammals. “Dolphins are truly exceptional creatures,” he says, turning away from his keyboard and gazing past the computer monitor out the window toward the blue of Sarasota Bay. Then he laughs. “Sometimes I regret sitting here listening on the radio to all the fun the graduate students are having,” he says. “I miss that, but the work is still challenging. Getting the answers is like Christmas morning—only now it’s like looking over someone else’s shoulder while she unwraps the presents.”