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Dolphins are one of the most visible, intriguing and
charismatic creatures of the sea, yet we know very
little about what they’re doing underwater.
Until now…
Our team has developed a tracking device that has provided
the first glimpses of dolphin behaviour from their perspective
and on their own terms. With this information we can better
understand the daily life of dolphins, such as how they interact
with one another, how mothers raise their offspring, how they
find food, and how they use their habitat. We can also under-
stand how these animals might be impacted by threats such as
coastal development, shipping traffic, vessel noise and interac-
tions with fishing gear. Putting all of this together will help us
to protect them.
Studying Wild Dolphin Behaviour
Dolphins are notoriously difficult to study in the wild. They have
a small body size, are fast-moving and live in groups that can
contain 1000 or more individuals.
Traditionally, dolphins have been observed from small
research vessels that travel alongside the group. However, as
dolphins spend only a small fraction of their time at the surface,
scientists are unable to see many behaviours and social inter-
actions. In addition, it’s nearly impossible to follow a single
individual in these large dolphin groups. Therefore, observations
are often taken at the group level, which may obscure impor-
tant individualistic behaviour.
For the past 20 years, researchers have been attaching video
cameras to large cetaceans such as humpback whales, blue whales
and sperm whales. This has provided detailed information
about the movement and behavioural patterns of these species.
However, the small body size and fast nature of dolphins
prevented researchers from successfully deploying miniaturised
cameras on them. Our multidisciplinary team developed a
special technique for attaching our cutting-edge C-VISS
(Cetacean-borne Video camera and Integrated Sensor System)
device to dolphins.
A New Dolphin-Tracking Device
Our video camera was modelled on a system developed to record
the behaviour of seabirds. However, attaching a video camera
to a dolphin comes with a unique set of challenges that differ
from seabirds. For example, while it’s possible to capture a
masked booby to attach the camera, it’s not possible to capture
a dolphin so we had to develop a specialised pole to deploy the
device. While it’s possible to tape the camera to the tail feathers
of a seabird, it’s not possible to do the same on dolphins so we
had to develop a special attachment method using suction cups.
Finally, dolphins dive deeper than boobies so we had to ensure
that our system was both waterproof and strong enough to
withstand the increasing pressure during deep dives.
While the video camera is the central component of our device,
C-VISS contains additional instruments to help us to understand
dolphin behaviour. A time–depth recorder measures the diving
behaviour, allowing us to understand how deep and for how long
a dolphin carrying the device is diving. C-VISS also contains satel-
lite and VHF transmitters that help us track the dolphin while
it’s tagged and to recover the device once it falls off the dolphin.
32 ||NOV/DEC 2017
The Secret Life of Dolphins
HEIDI PEARSON & GABRIEL MACHOVSKY-CAPUSKA
New underwater camera technology has captured the social lives of wild dolphins for the first
time, revealing how deep and for how long they dive, how they nurture their young and even
how they play with objects in the ocean.
C-VISS is archival, so it must be recovered to download the
data. The video camera, depth logger and transmitters are held
in a special float that is durable enough to withstand the pres-
sure increases that occur while a dolphin dives, yet light enough
that it is buoyant. When the suction cups detach from the
dolphin, the device floats to the surface, sending a signal to a satel-
lite with the approximate geographic coordinates. Once we
arrive in the area, we use a VHF antenna to find the device.
Importantly, C-VISS is non-invasive and does not harm the
dolphin carrying the device. We conducted a series of trials
with a Pacific white-sided dolphin at the Vancouver Aquarium
and several dusky dolphins in the wild, and we did not detect
any negative impacts of the device on the dolphins. One tagged
dolphin appeared to be so undisturbed by C-VISS that we even
observed it sleeping at the surface!
Meet the Dusky Dolphin
Working with our project partners at the New Zealand Depart-
ment of Conservation, Massey University and the US National
Oceanic and Atmospheric Administration, we spent 2 years
developing, refining and testing the device. We then tagged
eight free-swimming wild dusky dolphins off the coast of Kaik-
oura (Fig. 1), and obtained nearly 9 hours of video footage. The
longest attachment duration was 5 hours while the shortest
attachment duration was 9 minutes. The attachment duration
depends on a variety of factors, including where the device is
placed on the body, the strength of the suction cups and the
dolphin’s behaviour.
Dusky dolphins are bioindicators: any changes we observe
in their distribution, abundance and behaviour indicate larger
changes in the ecosystem. We have been making boat-based
observations of duskies since 2004, and this gives us a good
understanding of their behaviour at the surface. However, we
have always wondered what they were doing underwater.
Kaikoura is a perfect place for studying duskies because
approximately 1000 individuals occur off the coast at any
given time.
During the day, duskies are typically found near the coast
where they socialise, rest and travel in large groups. These groups
can be quite boisterous as individuals perform an amazing array
of leaps including backflips, somersaults, side slaps and belly
flops.
During the night, duskies move away from the coast to feed
on fish and squid in the waters of the Kaikoura Canyon. Once
this midnight feast is over, the dolphins return to the coast in
the early morning hours where they start the cycle over again.
A Day in the Life of a Dusky Dolphin
For the first timewe are seeing the behaviour of wild dolphins
from their perspective, and getting an indication of what a day
NOV/DEC 2017 ||
33
in the life of a dusky dolphin is like. Our video footage has even
revealed instances where the dolphin was filming our research
boat!
What have our data revealed? For example, how social are
they? How do mothers care for their calves? What is their habitat
like? How deep, how often, and for how long do they dive?
We are seeing how social individual dolphins are. We can
quantify this by recording the number of individuals swim-
ming with a tagged dolphin at any given time, and by looking
for signs of affection such as flipper rubbing: dolphins show
friendliness by gently extending their flippers to touch another
dolphin’s flipper or other part of the body.
34 ||NOV/DEC 2017
Figure 1. The C-VISS tag is attached to a dusky dolphin with suction cups.
Figure. 2. Video stills from C-VISS showing mother–calf swimming behaviour. Left: A dolphin calf swims side-by-side with its mother
in the echelon position. Right: A dolphin calf swims underneath its mother in the infant position.
We are also seeing how mothers care for their calves. A calf
typically swims in one of two positions near its mother (Fig.
2). It will swim beside its mother in echelon position, which
helps the calf to get a “free ride” by riding the pressure waves
created by the swimming action of its mother. A calf will also
swim underneath its mother in infant position. This may
provide protection from predators as the calf is physically tucked
under its mother. Additionally, when viewed from below, the
mother–calf pair looks like one large dolphin (Fig. 3), which may
be a deterrent to predators such as sharks. We are even seeing
intimate behaviours such as calves nursing (drinking their
mother’s milk), which for most dolphin species is virtually
impossible to be seen by researchers on the surface.
We are also seeing how dolphins use their habitat, from kelp
forests to the sandy sea floor to depths beyond the sunlit zone
where the sea becomes dark. We are also seeing how dolphins
interact with their habitat, for example by playing and “wearing”
kelp on their flippers (Fig. 4).
Finally, we can correlate all of these behaviours with data
obtained from our time–depth recorder. This helps us to deter-
mine how behaviour changes according to how deep and for how
long the dolphin is diving.
Future Research Directions
All that we have seen so far is revealing the complexity of the
lives of dolphins, yet we are just breaking the surface with the
power of this new research tool. We foresee several important
future research directions.
Understanding the nutrition of wild marine predators, such
as dolphins, is a challenge that science has yet to solve. We need
to know exactly what the food and habitat requirements of
marine predators are. Learning more about their feeding patterns
on a daily basis and what nutrients they contain will be
immensely useful for protecting endangered species.
As we continue to study duskies and other dolphin species,
we can better monitor and understand changes to the marine
environment. As we continue to monitor dolphins and corre-
late fine-scale information on their social, foraging and diving
behaviours with data on how the ocean is changing with respect
to sea surface temperatures, circulation patterns and plankton
abundance, we will have a better understanding of how climate
change is affecting other, less visible marine organisms.
Last but certainly not least, seeing the world through the
eyes of a dolphin will help us to better protect them. The more
we understand about how individual dolphins find food, care
for their young, find mates and avoid predators, the better we
can conserve them by establishing protected areas and developing
policies that limit human interference with these behaviours.
Heidi Pearson is Associate Professor of Marine Biology at The University of Alaska
Southeast. Gabriel Machovsky-Capuska is Loxton Research Fellow at The University of
Sydney.
NOV/DEC 2017 ||
35
Figure 3. Video stills from C-VISS showing a dolphin calf swimming.
From below, the mother–calf pair looks like one large dolphin,
which could help to protect them from predators like killer whales.
(Image quality is a function of video camera resolution.
Figure 4. A video still from C-VISS showing a dusky dolphin
swimming through kelp and draping it over its head. This is a form
of play behaviour. The dolphin’s head and C-VISS antenna are
visible.