Brain Power Big brains help dolphins adjust to captivity, but can they help captive dolphins readjust to the wild? Jeff Foster and the Born Free Foundation hoped so. Tey rescued Tom and Misha from Hisarönü in hopes of returning the dolphins to the open ocean. Attempts at freeing captive dolphins have
oſten failed because the animals simply didn’t remember how to be wild. Before they could be released, Tom and Misha needed reminding. And Foster, a marine mammal expert with 40 years experience, was just the guy to do it. On arrival at the dolphins’ new sea pen
near Izmir in Turkey, Foster knew he was in for a challenge. First, Tom and Misha had to regain their strength. Using traditional dolphin training methods, Foster taught the pair to do wind sprints, laps, tail walks, and jumps, building the speed and power they’d need to catch live fish or evade a hungry shark. Wild dolphins spend 80 percent of their
time underwater. Like most captive dolphins, Tom and Misha spent 80 percent of their time at the surface—feeding, training, and performing. Foster needed to shiſt their orientation away from humans and increase their independence. Te pair had forgotten that live fish were edible—they watched mullet swimming through the pen as though watching fish on TV. Tey didn’t realize they were food.
Learning to Hunt On shore, Foster set up a giant slingshot to shoot frozen fish into isolated areas of the pen. Te device helped the team to teach Tom and Misha that food was in the water, not in a trainer’s hand. Tom and Misha quickly caught on, responding to the thwap of the slingshot. “Tese animals are so smart that they figure things out,” Foster says. Next, Foster introduced a hole-studded
underwater feeding tube. Tom and Misha had to work out how to prod the tube so fish popped out through the holes. Ten Foster mixed their favorite frozen mackerel with fresh local fish species that were stunned so they moved slowly.
8 NATIONAL GEOGRAPHIC EXTREME EXPLORER
At first, the dolphins didn’t know what
to do. “It’s been one of these projects where you take two steps forward and one back,” Foster says, “and sometimes we’re actually taking two steps back.” But as Tom and Misha adjusted to chasing their meals, Foster installed remote-controlled buckets at different depths in the pen. Filled with wriggling fish, the lids popped open in different places and at random intervals, mimicking the unpredictable hunting conditions dolphins face in the wild. Soon, Tom and Misha began echolocating, searching the pen for food. Tey also invented a new hunting strategy, blowing bubbles to chase fish out of crevices they couldn’t otherwise reach.
Back to the Blue Twenty months aſter their rescue, Foster thought the dolphins were ready. A scuba diver entered the sea pen and unzipped the gate. Te Born Free team held their breaths, expecting Tom and Misha to flee immediately. But nothing happened. Te dolphins seemed suspicious and wary,
as if they suspected a trick. Aſter twenty minutes of anxious waiting, a trainer gave them the signal to swim. Tom obeyed and swam out of the gate but paused about 10 meters away. Ten Misha, suddenly understanding the opportunity, raced past Tom and led the way to freedom. “Within six hours they were catching wild
fish and swimming with another dolphin,” Foster says. “It was fabulous.” Using signals from GPS tags on the dolphins’ dorsal fins, the team continued to track Tom and Misha’s progress. When the tags fell off six months later, both dolphins were still swimming free.
WORDWISE behavior: the way in which an animal acts in response to a stimulus
captivity: confinement
echolocate: the location of objects by reflected sound pod: the basic social unit of dolphins
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24