Dolphin lovers are in a flap about a report claiming that their happy-go-lucky cetacean pals are thicker than goldfish. Helen Pid reports
How many elderly goldfish can moonwalk on water to Kylie? I’m wrestling with this question as Puck, a 41-year-old bottleÂÂnose dolphin, slides backwards across her 6m-deep pool, body upright, tail smoothly making waves to the rhythm of Can’t Get You Out Of My Head.
It looks special. Yet according to controversial remarks last month by a South African neuroscientist, Puck and her peers are dumber than goldfish.
It’s a hard claim to swallow, so I’ve come to the dolphinarium at Boudewijn Seapark in Bruges, Belgium, to investigate Puck, Roxanne, Flo, Yolta, Milo and other alleged dimwits.
The Boudewijn trainers, indeed much of the dolphin-loving world, are outraged by 40-year-old Wits University neuroscience professor Paul Manger. In the Biological Reviews of the Cambridge Philosophical Society, Manger hypothesised that ”there is no neural basis for the often-asserted high intellectual abilities of cetaceans”. Despite their supersized brains, whales, dolphins and porpoises are thick.
This flew in the face of almost everything else published about the mammals. ”No one I’ve talked to in the scientific field takes the claim seriously,” snaps Lori Marino, senior lecturer in neuroscience at Emory University, Atlanta.
The dolphin partly owes its reputation to what scientists call the ”encephalisation quotient”, the relative amount of brain per unit of body size. Modern humans possess the highest encephalisation of mammals, as our brains are seven times bigger than you would expect for our body size, but dolphins are close behind.
There is recent evidence for dolphin intelligence. In May, researchers from St Andrews University in Scotland reported that bottlenose dolphins adopt ”signature whistles” to identify each other, like humans use names. Last year, Australian researchers noted that some dolphins use tools — bits of sponge foraged and attached to their snouts — to stop their noses scraping against coral as they fish. The Irrawaddy River dolphins in Burma (now Myanmar) help local fishermen by corralling fish into their nets.
Perhaps best of all, researchers allegedly taught dolphins to ”sing” the Batman theme tune. I was pretty sceptical about that one till I came to Belgium. In a highlight of Boudewijn’s live spectacle, a girl is plucked from the audience and shown how to ”conduct” the dolphins in a round. She wrings both hands as if opening jars, which keeps the dolphins in time as they ”sing” (yelp) along.
The mammals appear to understand other signs. With a flick of the trainers’ wrists, they can open their mouths as if laughing, wag their heads and blow bubbles like smoke rings in the water.
Manger would say this indicates stimulus-response conditioning — which can be taught by a good trainer. The dolphins are certainly encouraged by the promise of mackerel and pilchards, and high-pitched toots on the dog whistles round the trainers’ necks.
Manger concedes dolphins have bigger than average brains — some weighing in excess of 8kg — but argues that this has nothing to do with Stephen Hawkingesque neurological brilliance. The dolphin brain is not built for complex information processing, but to counter the thermal challenges of being a warm-blooded mammal in a cold-water world.
He adds: ”You put an animal in a box, even a lab rat or gerbil, and the first thing it wants to do is climb out of it. If you don’t put a lid on top of the bowl, a goldfish will eventually jump out to enlarge the environment it is living in. But a dolphin will never do that.”
After the live spectacle, I watch two dolphins swim diligently in a tiny holding pool while their pals in the main tank practise double somerÂÂsaults with the trainer. The sidelined pair can jump the necessary distance, but like obedient children, only enter the main pool when their underwater trapdoors are opened.
So Manger’s observation may be correct, but does this tell us anything useful? Not according to Emory University’s Marino.
”That study with the goldfish he’s talking about was never published,” she says. ”It was presented at a meeting in 2000 and never peer-reviewed. It had so many flaws, I don’t know where to begin.”
Marino concedes dolphins have problems jumping over tuna nets, for example, but insists this says nothing about their intelligence. ”Dolphins, like humans, get stressed very easily — in fact, they can die of stress — and when they panic, they can’t think straight.”
But according to Manger, Marino and her doubting colleagues are just blinkered. ”People just don’t want to believe it,” he said. ”It’s a knee-jerk reaction. I think it’s kinda cute that people are so upset about it.”
Not everyone sees the cute side. Dolphins, with their happy, toothy ”grins” and impressive repertoire of tricks and emotions, are universally loved — 77 000 people belong to the Whale and Dolphin Conservation Society worldwide — and slagging them off is heresy.
Manger has even been accused of leading dolphins to an early grave. One South African dolphin expert, Nan Rice, who has worked for 35 years with the Dolphin Action and Protection Group in Cape Town, says Manger’s research could make it easier for humans to exploit them — and even drive them to extinction.
One big problem with discussing dolphin neurology is the ban on invasive experiments of the cetacean brain under laws protecting marine mammals. Unlike rats, you can’t just dig around in a dolphin while it is still alive. And for practical and ethical reasons, the vast majority of experiments have been conducted on dolphins born in captivity. How representative are these animals of the species?
The other major stumbling block is defining intelligence. There is no reliable, universally accepted measure in humans. A Mensa test? Those multiple-choice quizzes in women’s magazines?
But contrary to Manger’s claim, many experiments indicate that dolphins aren’t just pretty snouts. One of the most interesting, by Marino and Diana Reiss, regards self-recognition. In 2001, they showed that dolphins can recognise themselves in a mirror — a skill previously thought to be unique to humans and apes.
The scientists exposed two bottleÂÂnose dolphins to reflective surfaces after marking them with black ink, ”sham-marking” them with a water-filled marker or not marking them at all. The team predicted that if the dolphins recognised their reflections, they would not show social responses; they would spend more time in front of the mirror when marked; and they would move to the mirror more quickly to inspect themselves when marked or sham-marked.
The experiments bore out all three predictions. The animals even selected the best reflective surface to view themselves — showing they are aware of themselves as individuals, which takes a high level of cognitive skill.
Johan Cottyn, head trainer at Boudewijn, is most impressed by how their dolphins have been trained to accept medical interventions without fuss. ”One needed a daily injection for a kidney problem. It really hurt her, because the needle had to cut through blubber, but she seemed to understand she needed the jab to survive, and came for it automatically every day.”
Boudewijn dolphins can communicate more than they have been taught, Cottyn says. ”Once, when one was giving birth the baby got stuck halfway. The mother rubbed her belly to show us where the problem was.”
Her colleague Piet de Laender has no time for those who anthropomorphise dolphins. ”They’re not humans, and trying to judge them by human standards of intelligence is pointless,” he insists. — Â