Great White Sharks are usually
only brought into captivity because they are sick or injured.
Great White Sharks
are not usually kept in captivity as they do not survive
long. Here are two documented examples of these sharks successfully
being put into a captive situation and then released.
- A young female shark at the Monterey Bay Aquarium in Monterey,
CA where she was kept for 198 days from September 2004 until released
in March 2005.
- Another female shark brought to the
Steinhart Aquarium in San Francisco, CA in August 1980 where she
was kept for 72 hours and then released.
Dr. Jungle, "This
is the ONLY top predator that has not been kept in captivity
or tamed by man!"
Monterey Bay Aquarium:
White Shark Research Project
Caught in a commercial fishing net in August 2004,
a young female Great White Shark was received by the Monterey Bay
Aquarium and this is what they report about her.
..."She was tagged and held in an ocean pen until September 14. She remained in good
health and was transported to Monterey and placed in the Outer
Bay exhibit. During her 198 days in the aquarium's million-gallon
Outer Bay exhibit, she grew from a length of 5 feet and a weight
of 62 pounds to a length at release of 6-feet-4½ inches and a weight
of 162 pounds. "The shark was tagged and successfully released back to the wild
in March 2005."... Monterey Bay Aquarium.
To learn more about this shark in captivity, visit
the aquarium's
White
Shark
Research Project
Electroreception
by R. Aidan Martin
Director of the ReefQuest Centre for Shark Research,
a Research Associate of the Zoology Department of the University
of British Columbia, and an Adjunct Professor of the Oceanographic
Center of Nova Southeastern University.
The main topic of Mr. Martin's
article is electroreception, an acute sensitivity to electrical
fields demonstrated by sharks and rays. In his article he discusses
the unique opportunity "Sandy", a healthy female Great
White Shark in temporary captivity, provided to learn more about
it. Here he tells us about her brief stay at the Aquarium.
"The 72-hour captivity of a 7.5-foot (2.3-metre), 300-pound
(136-kilogram) female White Shark at San Francisco's Steinhart
Aquarium during August 1980 provided an unexpected opportunity
to measure the electrosensitivity of this species. Dubbed 'Sandy',
the juvenile Great White was displayed in Steinhart's torus-shaped
'fish roundabout', becoming an instant media celebrity and drawing
some 40,000 visitors to the Aquarium over a three-and-a-half-day
period. By the fourth day of her captivity, Aquarium director John
McCosker noticed that Sandy continually collided with a particular
five-degree arc of the tank."...R. Aidan Martin
To learn more about "Sandy" at
the Steinhart Aquarium
Read Mr. Martin's
article:
Electroreception |
Distribution:
The Great White Shark is found throughout the world's oceans, mostly
in cool coastal waters. They can cover great distances
and larger sharks have been seen journeying across the great ocean basins.
The number of these sharks in not known but their numbers are believed to be declining. Individuals identified by scars
and other markings, or tagged, have been observed returning for several
years to the same locality while many of the tagged sharks simply disappear.
Though generally solitary animals, they are occasionally seen traveling
in pairs.
Size:
A very large species of shark, the Great White is the largest of
the aggressive meat-eating sharks followed by the Tiger Shark. It is
not known how large this shark can get, but the largest one recorded
was 21' long (6.4 m) and weighed 3312 kg. Newborn shark pups are about
4' - 5' (122 - 152 cm) long, with the smallest one measured at 47" (119
cm). Most Great White Sharks average about 12 - 16' (3.7-4.9 m) long
with the larger ones being found in south Australia.
Description:
The Great White Shark has a torpedo-shaped body with a pointed
snout, five gill slits, and a powerful crescent shaped tail which propels
them through the water. They are grey on the top and white undermeath.
Their three main fins, the dorsal on top and two pectoral fins, are
used for balance. Four other minor fins; a small dorsal fin close to the tail, a pair of small pelvic fins, and a tiny anal fin, help with the way water flows over the sharks body. Their skeletons are made of cartilage rather
than bone.
They can have
up to 3000 teeth at any one time arranged in rotating rows that move
up to replace ones that become worn out or broken. The teeth are triangular
with serrations on the sides. Those on top are used for grabbing and
tearing their food, while the bottom teeth presumeably act more like spears that
hold the food securely in place.
Sharks are heavier than water and will sink if they don't keep moving. Though they do have a large oily liver which gives them some floating ability, they don't have a gas filled swim bladder like the bony fishes do. They also cannot swim backwards or come to an abrupt stop.
Swimming:
The Great White Shark is a graceful
efficient swimmer. They will cruise along the bottom or close to the
water's surface, seldom swimming at midwater depths. They can also make fantastic
leaps out of the water.
They are not the fastest swimming shark in the ocean,
that skill is found in the Shortfin Mako Shark Isurus oxyrinchs, which
can swim up to 60 miles (96.5 kilometers) per hour. The Great White Shark usually
cruises at about 2 miles (3.2 kilometers) per hour, but can make quick short
pursuits at about 15 miles (24 kilometers) per hour.
Feeding:
To obtain food they use primarily two senses; an extremely acute
sense of smell, and an incredible keen ability, called electroreception,
to sense electrical fields that are generated by all animals. These
electrical fields are emitted by simple things such as skin coming
in contact with the water, a contracted muscle, or the flow of blood into
the water from a wound.
The
young sharks eat rays, other sharks, and some fish. As they get larger they
eat larger foods such as tuna and other big fish, small toothed whales,
and sea turtles, but are noted as being especially fond of pinnipeds
(sea lions and seals).
There are no natural predators of the Great White Shark, they
are at the top of the food chain.
Great White Sharks
are opportunistic feeders but they also eat carcasses they find,
especially large whales, and will snack on fish caught on the lines
and nets of fishermen.
They swim along the bottom, and come up to their chosen prey from underneath in a quick burst of speed, often leaping out of the water.
They usually attack their food fiercely and then often wait
a bit after the initial attack to grab the food consume it. They do
not chew their food, but rather use their teeth to rip it into mouth sized
pieces which they swallow whole. One big meal can satisfy a shark for
up to 2 months.
There are some critters they don't like to eat!
They don't eat sea birds. They
have been seen coming up beneath them and bouncing them up in the air like a ball,
but they don't eat them. They also don't eat Sea Otters. Though they will often bite
them, sometimes fatally, they have not yet been found in a shark's belly.
Breeding:
Though not much is yet known about the mating behavior
of these sharks, females reach maturity at about 10-12 years bearing
their first young at about 12-14 years old. These sharks
are oviviparous so
the eggs are fertilized in the female, they will hatch within
the female too. There is no placenta so the young get no nourishment
from the mother, rather they eat unfertilized eggs and smaller siblings.
The female gives birth to 2 - 14 fully formed pups which are on their
own as soon as they are born.
Newborn shark pups are about 4' - 5' (122 - 152 cm) long and will grow
about 10" (25 cm) a year to maturity. |
