1. OFTHESEA
A garbage can with fins, waste-
basket of the sea, the bane of
surfers … the tiger shark enjoys
a reputation of being as fierce
and dangerous as its terrestrial
namesake. But, as new research is
showing, this is not entirely justi-
fied. We may never think of them
as pussycats, but as a dedicated
team of researchers and dive oper-
ators enhances our knowledge of
tiger sharks, so public perception
of this striking-looking predator
is slowly changing. Save Our Seas
Foundation Ocean Correspondent
Cheryl-Samantha Owen finds
out more about these ocean stars
with stripes.
TEXT BY CHERYL-SAMANTHA OWEN
PHOTOGRAPHS BY THOMAS P. PESCHAK/
SAVE OUR SEAS FOUNDATION

48 A F R I C A G E O G R A P H I C • m a y 2 0 1 0

2. 50 A F R I C A G E O G R A P H I C • m a y 2 0 1 0 51w w w. africageographic . co m
A
rmed with an arsenal of
gear, including acoustic and
pop-up archival satellite
tags, underwater radio lis-
tening stations, cameras, a
modified tagging speargun
and shark slings, the neoprene-clad
researchers that brave the waves off South
Africa’s east coast are not your average
white-lab-coat data crunchers. Vic
Peddemors of the University of KwaZulu-
Natal and Macquarie University, Australia,
Malcolm Smale and Matt Dicken of
Bayworld Centre for Research and
Education in Port Elizabeth, and shark-
diving expert Mark Addison, have spent
countless hours at sea. Initiated and fund-
ed by the Save Our Seas Foundation (SOSF),
their mission is to uncover the secrets of
the infamous tiger shark Galeocerdo cuvier.
First described in 1822, the genus name
Galeocerdo is derived from the Greek galeos
or ‘shark’ and the Latin cerdus, while the
species name cuvier honours 18th-century
French naturalist Georges Cuvier. The
tiger shark is one of the world’s largest
predatory fish, growing up to five metres
(and possibly even as long as 7.2 metres)
in length and weighing as much as 1000
kilograms. Its broad, blunt snout and large
black eyes are unmistakable, and its
unique saw-edged and cockscomb-shaped
teeth cater perfectly for the appetite they
have to sate.
The exquisite beauty of the tiger shark’s
skin may seem to pay homage to its furry,
jungle-inhabiting namesake, but as sharks
evolved millions of years before their
mammalian counterparts, nature’s patent
on tiger stripes was actually registered at
sea. In clear water, light dances on the
sharks’ backs, jumping across the vivid
bars and spots (which fade from black to a
gentler grey with age) and highlighting
the golden sheen that coats their skin like
molten honey. In motion they are hyp-
notic, their purposeful swimming a cul-
mination of elegance and grace developed
over millennia.
Colloquially, they are
known variously as ‘a
garbage can with fins’,
‘wastebasket of the sea’
or more sinisterly as
‘the man-eater shark’
and ‘bane of surfers’.
Their bad rap stems
partly from some of
the items found in the
stomachs of captured
animals and partly
from occasional attacks
on surfers and divers in
the tropics. The discovery of licence
plates, pieces of rubber tyres, seabirds, sea
snakes, marine iguanas and even the
tattooed arm of a murdered mobster
explains why these sharks are thought to
have a diet more indiscriminate than that
of a goat.
Although indigestible garbage (and even
human remains) sometimes does end up
in the guts of scavenging sharks, their
natural and preferred prey, depending on
their geographical region, includes sea
turtles, bony fishes, sharks, rays, seabirds,
dolphins and squid. Studies of the diets of
tiger sharks found off South Africa’s east
coast show that rays and other sharks
form the most significant part of their diet
– tiger sharks in other locations consume
far less of these species. These studies also
concluded that tigers probably play a crit-
ical role as apex predators in regulating
dolphin populations along the KwaZulu-
Natal (KZN) coast, and that they have a
surprising taste for toxic puffer- and por-
cupine fish.
Tiger sharks use the specialised struc-
ture of their teeth – heavy, oblique cusps
with coarse serrations – together with a
rolling jaw motion to saw prey apart and
to bite through hard, bony turtle shells.
Sea turtles seem to appear regularly only
on tiger shark menus; no other shark is
known to prey on them consistently.
Indeed, fossil records show that tiger
sharks evolved during the same period as
the tough-armoured sea turtles – about
100 million years ago during the Upper
Cretaceous.
Solitary feeders that hunt primarily at
night, tiger sharks either head into deeper
oceanic water or move closer inshore as
darkness falls, depending on their loca-
tion. They often hunt in turbid water and
where fresh water flows into the sea. As
they grow, so the structure of their teeth –
and their diet – changes. Younger sharks
tend to target inshore reef fish, moving up
the food chain to turtles, birds and sharks
when they are larger.
This wide spectrum of
culinary choice may be
one of the secrets to
their survival. Tiger
sharks are very large
animals and require
megadoses of kilojoules.
The fact that they are
able to take such advan-
tage of the marine smor-
gasbord means that they
are less likely to run
out of food than more
selective feeders.
RIGHT Younger tiger sharks
are painted with dark, almost
black stripes and spots. As they
age, these striking markings
will fade to a light watermark
pattern.
PREVIOUS SPREAD A tiger
shark emerges from the crystal-
clear depths of the Indian
Ocean. Conservationists are
working relentlessly to ensure
that these threatened sharks
don’t become grey ghosts of
our watery world.
THE EXQUISITE
BEAUTY OF THE TIGER
SHARK’S SKIN MAY
SEEM TO PAY HOMAGE
TO ITS FURRY JUNGLE-
INHABITING NAMESAKE

SEA TURTLES
SEEM TO APPEAR
REGULARLY ONLY
ON TIGER SHARK
MENUS; NO OTHER
SHARK IS KNOWN
TO PREY ON THEM
CONSISTENTLY
N
U
SOUTH
AFRICA
(KW
AZULU-NATAL)
INDIAN
OCEAN
Aliwal Shoal
• Durban
• Amanzimtoti
• Umkomaas
• Scottburgh
N2

3. A
mzani, jarjur knaza and ma’o tore
tore – the Swahili, Arabic and
Tahitian names for the tiger
shark point to just a few of the
locations it frequents. A relatively com-
mon coastal and open ocean species, it
can be found from the waters around
oceanic islands to estuaries, and it inhab-
its tropical and warm-temperate seas
throughout the world. In Africa, the spe-
cies ranges from Cape St Francis on South
Africa’s southern coast up the east coast to
the Red Sea, and from Morocco in the
west possibly as far south as Angola.
In South Africa, a near-shore reef called
the Aliwal Shoal, which lies five kilometres
off Scottburgh on the KZN coast, is known
as Tiger Shark Central. Constantly frequent-
ed by a suite of other cartilaginous fish,
from ragged-tooth and blacktips to dusky
sharks, the shoal – a marine protected area
or MPA – is a shark lover’s hotspot. Tigers
are also often found off Protea Banks and
Ponta d’Ouro in Mozambique, but at Aliwal
Shoal they are almost always encountered
during the warmer season from December
to June. Happily, this coincides with the
province’s peak tourist season and in recent
years a thriving shark-diving industry has
sprung up around the reef (see ‘Dancing
with Tigers’ on page 58).
Tag-and-release data in the US have
shown that while some tiger sharks
remain in one place, others travel great
distances. In tropical areas they are often
present year-round, whereas in warm-
temperate areas such as the Aliwal Shoal
there is a seasonal abundance of tigers
during the warmer months. It seems that
tourists are not the only species to vacate
the KZN coast in winter; most of these
cryptic predators disappear each year
when the water temperature drops.
Addison, the owner of Blue Wilderness,
an underwater filming logistics and ex-
peditions company, has been observing
tigers at Aliwal for more than a decade.
For him, ‘diving with tiger sharks over
the past 14 years has been one of the un-
doubted highlights of my diving life as
well as being a great myth exploder’. He
has noted that 97 per cent of the indi-
viduals he’s seen here are females, with
few sightings of immature or male sharks
and none of pups. Some of the smaller
females frequent the shoal throughout
the year, but the three-metre-plus mature
females visit only between February and
May, when the visibility is good and the
seas are calm and warm. Temperature,
breeding or food availability may play a
part in their movements, but scientists
are still trying to piece together the clues
that will tell us why they come and why
they go.
‘Understanding the tiger shark’s local
and regional movements and how it uses
its habitat is essential for making
informed conservation decisions about
protecting the species,’ says SOSF Director
Chris Clarke. ‘Answering research ques-
tions to a high degree of accuracy is often
less complicated on land than in the sea,
where large marine animals such as
sharks range across ocean basins, making
observation difficult.’
T
he SOSF tiger shark research pro-
ject was started in 2006 to improve
current understanding of this
important apex predator. ‘We
hope the results of our research will also
be used to develop sound advice for divers
and swimmers along this coast,’ says
Clarke. Information gained from tiger
shark research is proving invaluable for
global conservation efforts aimed at pull-
ing the species back from the precipice.
The study has focused on four aspects of
tiger shark research. Behaviour and
53w w w. africageographic . co m52 A F R I C A G E O G R A P H I C • m a y 2 0 1 0
ABOVE Like all sharks, tigers
have multiple rows of teeth
along the edges of their jaws.
Throughout their lives, they are
able to replace old teeth with
new ones using this dental
‘conveyor belt’.
RIGHT Tiger sharks possess a
‘sixth’ sense that humans lack:
‘electroreception’. The tiny
black dots visible on their snout
and head are pores that lead
into small, interlinked cavities,
known as the ampullae of
Lorenzini. Filled with a con-
ductive jelly, the ampullae are
sensitive electrical field detec-
tors used for tracking prey.
OVERLEAF With a satellite
tag firmly attached to its
dorsal fin, a female tiger
shark is released from a spe-
cially designed shark sling.
This individual remained calm
throughout the process, never
turning on her captors.

SCIENTISTS ARE
STILL TRYING TO
PIECE TOGETHER
THE CLUES THAT
WILL TELL US WHY
THEY COME AND
WHY THEY GO

4. 54 A F R I C A G E O G R A P H I C • m a y 2 0 1 0

5. 56 A F R I C A G E O G R A P H I C • m a y 2 0 1 0 57w w w. africageographic . co m
movements off the KZN coast are tracked
using acoustic tagging techniques; long-
range movements are plotted by pop-up
archival satellite tags; manual tracking is
done via pinging V16 tags; and photo-
graphic ‘body-printing’ of individual tiger
sharks is ongoing.
One would imagine that tagging a
mature female tiger shark is a bit like dan-
cing with wolves (chaotic and potentially
lethal), but in fact the sharks are remark-
ably cooperative and the team runs a slick
operation. First, Addison free-dives down
to a shark and places a hook in the corner
of its mouth. Then the boat crew brings
the animal to the surface and quickly calms
it by placing a plastic cover over its eyes.
With the shark pinned to the boat in a
tailor-made sling, holes are rapidly drilled
through its dorsal fin with a specialised
corer that also provides genetic samples.
Once the tag is bolted to the fin, the
shark is released. Rather than turning on
its captors, it swims away. ‘The fact that
the sharks often return to baited dives
shortly after the experience suggests that
they are not in pain or traumatised,’ says
Peddemors.
Three of the four pop-up archival satel-
lite tags deployed revealed a startling pat-
tern in the sharks’ journeys (the fourth
malfunctioned, leaving its subject’s where-
abouts a mystery). When Smale down-
loaded the dive profiles recorded by the
satellite, a vertical line marking each dive
zigzagged across the screen. The saw-
tooth pattern it formed was characteristic
of a shark ‘bounce-diving’ through the
water column. The tiger sharks were con-
ducting frequent dives to more than
300 metres, constantly moving from the
surface to the seafloor and up again. One
shark even descended below 800 metres,
breaking its tagged Hawaiian cousin’s
record for maximum swimming depth by
a factor of almost three.
Aside from revealing an incredible div-
ing aptitude, these results show that the
animals travel through temperatures that
vary by as much as 10 °C, suggesting that
the tiger shark is not confined to being a
‘warm-water and tropical’ species as was
previously thought. Utilising the entire
water column, especially in the open
ocean where food is scarce, is like hunt-
ing in 3D rather than 2D. It allows the
shark to pick up the scent trails and other
signals of potential prey across the whole
ocean larder, instead of being confined to
a single shelf.
Similar bounce-diving behaviour was
observed by Dicken via a boat-based
receiver. He conducted multiple daytime
tracks of tigers using continuous pinger
tags that transmitted depth and temper-
ature information about the sharks being
tracked to the boat. Subsequently, the
team stalked a tiger shark for 24 hours.
This added a new dimension to the study
and gave immediate insight into how dif-
ferent individuals utilise the reef. It also
turned up surprises of a different sort. At
one stage, the shark swam beneath all
10 recreational dive boats without being
seen. Despite its species’ reputation, this
particular individual proved to be docile
and wary, and if anything, felt threat-
ened by the presence of the divers.
Eighteen VR2 listening stations were
deployed in a grid pattern within the
Aliwal Shoal MPA. Acting as the ears of the
reef, they recorded the movements of
tagged sharks whenever they roamed the
area. In March 2007, however, a gargan-
tuan storm struck the coast, and its
14-metre waves and six metres of sediment
erosion destroyed most of the stations
ONE WOULD IMAGINE THAT TAGGING A MATURE FEMALE TIGER SHARK
IS A BIT LIKE DANCING WITH WOLVES – CHAOTIC AND POTENTIALLY LETHAL
ABOVE New research shows that
tiger sharks ‘bounce dive’, des-
cending rapidly to depths of
several hundred metres then
resurfacing, proving that they
can withstand colder tempera-
tures than was previously thought.
OPPOSITE, ABOVE Drilling the
tag onto the shark’s dorsal fin is
similar to piercing an ear or a
nose, as it is made of cartilage,
not bone. The fin is supported
by long fibres of collagenous
tissue, which provide the main
texture in sharkfin soup and are
the reason that 73 million sharks
are killed each year.
OPPOSITE, BELOW Mark
Addison swims away with
a newly tagged tiger shark,
confident that it has not
been traumatised.
Maximum size 7.2 metres and 1 000 kilograms.
Life cycle Female tiger sharks reach maturity at about three metres and/or
seven years of age. 14 to 16 months after they’ve mated, between 10 and
80 pups are born. The young are 60 centimetres at birth and can live for up
to 25 years.
Mythbuster The embryos of tiger sharks fight each other while in their mother’s
womb, the survivors being the baby sharks that are born. FALSE (this is how
ragged-tooth sharks do it).
Threats Fishing, both recreational and commercial. In addition to their meat,
sharks provide fins for soup, skin for leather and their livers are used to produce
vitamin A oil, which is used in skincare products and supplements.
tigers at a glance

6. 58 A F R I C A G E O G R A P H I C • m a y 2 0 1 0 59w w w. africageographic . co m
and the precious data they harboured.
The few units that survived revealed that
sharks return to the area many times dur-
ing the course of the day and come back
in multiple years. In addition, the photo-
graphic identification catalogue (based
on the unique patterns on the sharks’
dorsal and pectoral fins) is supporting
Addison’s visual sightings of the tigers
that return to the shoal each year. Much
of the data still awaits analysis, holding
promise of new discoveries.
‘O
ne of the most important
and exciting things about
the SOSF project is that it
assisted in breaking down
the barrier of belief across the world that
tiger sharks are ferocious man-eaters,’
says Peddemors. No formal protection for
the species exists and with most of their
time spent outside MPAs, the sharks face a
perilous ocean filled with longliners, unres-
tricted fishing and shark nets. In addition,
they may be affected by concentrations of
toxic pollutants contained in the prey they
eat. Over-exploitation from targeted and
bycatch fisheries, which kill the sharks for
their fins and flesh, has garnered the
mighty tiger shark, alongside many other
shark species, a place on the IUCN Red List
of threatened species.
KZN’s infamous shark nets (essentially
gill nets that ‘work’ by reducing popula-
tions) alone kill a reported average of
48 tiger sharks a year. In an area where
ecotourism dollars are earned because of
the presence of tigers, these deaths are bad
news. Dicken’s 2009 report on the value
of tiger shark dive tourism states that ‘…
the direct value of tiger shark diving to
the Aliwal Shoal region was just under
R12.5-million [around US$1.6-million]’.
As with many other species worldwide,
the tiger sharks that live off South Africa’s
east coast are more valuable alive for eco-
tourism and education than they are as
fins, jaws, teeth and meat.
The web of life within the ocean ecosys-
tem is so complex that we have not yet
uncovered all its secrets. We are still trying
to understand the role that many species
play in relation to their environment, but
it is safe to say that every species of shark
has adapted over millennia to a particular
habitat and the loss of any apex predator
has an impact. Sharks have survived for
some 400 million years – appearing at
least 200 million years earlier than the
dinosaurs and 396 million years before
the first hominids evolved.
Scientists and dive operators alike are
battling to save the tigers of the sea. In
the words of Mark Addison: ‘Of all the
sharks I have worked with, the tiger is by
far the most beautiful and gentle. Its slow
and elegant movement coupled with a
patient and unexcitable demeanour give it
a stately presence, inspiring feelings of
wonder rather than fear.’ So go on, take a
plunge into its world, bust a few myths
and you could help one of the ocean’s
most important apex predators to survive
its greatest challenge yet. Us. 
ABOVE The very best in marine
wildlife watching. Divers have
witnessed as many as 80 blacktip
and 15 tiger sharks in the water
around a suspended bait drum.
OPPOSITE Humans did not
evolve with sharks. We are
strangers in their world and
when we’re in the water with
them, we are possibly viewed
simply as other sharks. They
are curious creatures, however,
and sometimes swim over to
divers to investigate them
more closely.
‘OF ALL THE SHARKS I HAVE WORKED WITH, THE TIGER IS BY
FAR THE MOST BEAUTIFUL AND GENTLE. ITS ... PATIENT AND
UNEXCITABLE DEMEANOUR GIVES IT A STATELY PRESENCE,
INSPIRING FEELINGS OF WONDER RATHER THAN FEAR’
Yes, tiger sharks are big predators, but
knowledge of their behaviour has pro-
gressed to the point where, with the
right operator, free-diving with them is
a perfectly sane (and safe) thing to do.
Cheryl-Samantha Owen explains.
The sharks are attracted to a sardine-
filled perforated steel drum suspended
approximately five metres below the sur-
face of the water. The drum releases a pun-
gent brew of fish oils that moves with and
is distributed by the current. Sharks pick
up the scent and follow the ‘chum’ slick
back to its source, the boat. When a shark
is sighted, the buoyed drum is released
from its anchor to be taken up by the cur-
rent. The divers and snorkellers then drift
in the water column perpendicular to and
staying out of the chum slick. A safety diver
keeps watch from the surface, making sure
that divers do not drift into the slick.
When? The highest concentration of tiger
sharks at Aliwal Shoal is in the summer
months, from December to June.
Experience? Says Mark Addison from
Blue Wilderness, ‘We have taken our under-
standing of these magnificent animals to a
level where the experience needed is very
low – you can watch the sharks from the
boat, or surface snorkel, free-dive or scuba
dive with them.’
How safe is it? It’s all about choosing your
operator carefully. Blue Wilderness takes
some 1 500 people a year on shark-diving
expeditions, without incident.
For more information or to book a tour,
contact www.bluewilderness.co.za
DANCING
with tigers
Save our Seas Foundation
(SOSF) is a non-profit organisa-
tion that implements and sup-
ports scientific research and
educational projects focused
on the marine environment.
To learn more about tiger
sharks, their conservation and
how you can help, visit www.
saveourseas.com