12.2018 | THE SCIENTIST 17MIKE BOSSLEY
have known for many years that the
spatial focus of the spotlight could vary
in extent,” he says. “These new studies
show that there is also temporal discon-
tinuity: although attention may seem
continuous at a particular location, it
changes in time in accord with a low-
frequency rhythm.”
Even with this new insight, it’s
unclear why attention would func-
tion in this manner. One possibility is
that momentary lapses during a single
task could allow for refocusing atten-
tion at times when other goals, objects,
and events require it. While driving, for
example, it’s possible to attend to the
coffee, the road, and the conversation—
not because the brain is attending to all
three simultaneously, but because it can
quickly switch between them, says Ran-
dolph Helfrich, a postdoc in Knight’s lab
who led the study with human partici-
pants. “We show that the brain doesn’t
run in parallel when it comes to paying
attention, but rather rapidly sequen-
tially,” he says.
Grygori Buszaki, a neuroscientist at
New York University who was not involved
in the study, tells The Scientist that the
team’s findings lend support to the more
general idea that regions of the brain com-
municate with each other via the timing
of different activity patterns—not just for
attention, but for many cognitive pro-
cesses. From this point of view, “brain
rhythms comprise the needed syntax for
neuronal language,” he says. “Both studies
are compatible with this framework.”
—Phil JaeklWalking
on Water
Billie the Indo-Pacific bottlenose dolphin
liked to walk on water. She’d pump her
tail vigorously back and forth, forcing her
entire body out of the water, so she’d skim
backwards along the surface as if she were
moonwalking.
Mike Bossley, a researcher at the wild-
life charity Whale and Dolphin Conserva-tion (WDC), was the first to observe Billie
performing the trick; he caught her doing
it in the bays and estuaries around Ade-
laide, Australia, in the 1990s and early
2000s. At the time, it was common to
see trained dolphins tail walk in marine
parks. But Billie was wild.
“Tail walking in wild dolphins is
indeed rare,” says Janet Mann, a biologist
at Georgetown University who studies
dolphin behavior. “I have seen it only once
in 32 years of observing wild dolphins.”
Bossley’s now interested in what the
behavior reveals about how the animals
learn from one another. Billie probably
learned to tail walk during a brief stint
in captivity, he says. She was born off the
southern coast of Australia, then trapped
in a polluted harbor near Adelaide in 1987
and taken to a dolphinarium. She was
never trained to tail walk, but watched
the five other dolphins there train for
three weeks. She was then released back
into the wild.
In 1995, Bossley spotted Billie tail-
walking in Port River estuary, just north
of Adelaide’s city center. “I was out in
my red inflatable boat, and suddenly she
appeared right beside the boat and did
a tail walk circling around it only about
2 meters away,” he writes in an email toThe Scientist. He was surprised to see Bil-
lie tail walking, he says, but didn’t real-
ize the significance of the behavior at the
time—that a cultural trend was emerg-
ing among wild bottlenose dolphins in
the area.
That started to sink in as Bossley
watched Billie tail walk multiple times
over the next few years, and then spot-
ted another wild dolphin, Wave, doing it
too. “I became very excited when Wave
started to tail walk as well because I
then realized what was happening—the
behavior was spreading through the dol-
phin community,” he says. Bossley wanted
to document the behavior, so, that same
year, he enlisted the help of citizen scien-
tists. More than 30,000 hours of obser-
vation later, he and colleagues at WDC
described 11 dolphins—six adult females
and five juveniles of both sexes—doing
the tail walk between 1995 and 2014 (Biol
Lett 14:20180314, 2018).
Among adult dolphins, “it is unclear
why only females appear to tail walk, and
again, why only some of the local females
tail walk,” Bossley says. But the observa-PARTY TRICK: Dolphins are trained to tail walk
in captivity. But until recently, it was very rare
to see the behavior in wild animals.