GREAT WHITE SHARK
GREAT WHITE SHARK
The great white shark (Carcharodon
carcharias), also known as the great white, white pointer, white shark, or
white death, is a species of large mackerel shark which can be found in the
coastal surface waters of all the major oceans. The great white shark is
notable for its size, with larger female individuals growing to 6.1 m (20 ft)
in length and 1,950 kg (4,300 lb) in weight at maturity. However most are
smaller, males measuring 3.4 to 4.0 m (11 to 13 ft) and females 4.6 to 4.9 m
(15 to 16 ft) on average. According to a 2014 study the lifespan of great white
sharks is estimated to be as long as 70 years or more, well above previous
estimates, making it one of the longest lived cartilaginous fish currently
known. According to the same study, male great white sharks take 26 years to
reach sexual maturity, while the females take 33 years to be ready to produce
offspring. Great white sharks can swim at speeds of over 56 km/h (35 mph), and
can swim to depths of 1,200 m (3,900 ft).
Reproduction
Great white sharks were previously
thought to reach sexual maturity at around 15 years of age, but are now
believed to take far longer; male great white sharks reach sexual maturity at
age 26, while females take 33 years to reach sexual maturity. Maximum life span
was originally believed to be more than 30 years, but a study by the Woods Hole Oceanographic Institution
placed it at upwards of 70 years. Examinations of vertebral growth ring count
gave a maximum male age of 73 years and a maximum female age of 40 years for
the specimens studied.
Little is known about the great
white shark's mating
habits. It is possible that whale carcasses are an important location for
sexually mature sharks to meet for mating. Birth has never been observed, but
pregnant females have been examined. Great white sharks are ovoviviparous,
which means eggs develop and hatch in the uterus and continue to develop until
birth.
The great white has an 11-month gestation period. The shark pup's powerful jaws
begin to develop in the first month. The unborn sharks participate in oophagy,
in which they feed on ova
produced by the mother. Delivery is in spring and summer.
Great white shark
fact
1) Great
white sharks can be found throughout the world’s oceans, mostly in cool waters
close to the coast.
2) These
super swimmers are the largest predatory fish (fish that eat other fish or animals)
on our planet. On average, they grow to around 4.6m long, but some great whites
have been measured at 6m – that’s half the length of a bus!
3) Great
white sharks are grey with a white underbelly, from where they get their name.
They have a streamlined shape and powerful tails that propel them through the
water at over 60km per hour!
4) Any
creature unlucky enough to find itself in the gob of a great white is in for a
nasty shock! Because this marine beast’s mouth is equipped with a set of 300
sharp, triangular teeth arranged in up to seven rows. Yikes! Let’s take a
closer look, if you dare…
5) Whilst
many think of these beasts as fearsome man-eaters, humans aren’t, in fact, on
the great white’s menu. Phew! There are around 5-10 attacks a year, but
researchers believe that, rather than preying on humans to eat them, the sharks
are instead taking a “sample bite” out of curiosity, before swimming off.
6) So what do
they eat? Well, when they’re young, they feed on small prey, such as fish and
rays. But when they’re older and bigger, they generally feast on sea mammals
such as sea lions, seals and small whales.
7) Great
white sharks have such a strong sense of smell that they can detect a colony of
seals two miles away. And check this out – if there was only one drop of blood
in 100 litres of water, a great white would smell it!
8) These
cunning creatures like to take their prey by surprise. They usually position
themselves underneath their unsuspecting victims before swimming up and…chomp!
They often burst out of the water in a leap (called a breach) before falling
back in with their meal in their mouths.
9) When a
great white gives birth, she usually has two to ten youngsters, called “pups“.
But she shows no care for her offspring – in fact, she may even try to eat
them! Taking care of themselves, the newborn pups will immediately swim off
into the ocean
10) Great
white sharks are at the top of the food chain and aren’t likely to be killed by
other sea creatures. Sadly, however, they are under serious threat by human
activity. Illegal hunting of these beautiful beasts, and overfishing, have meant
that today great white sharks are an endangered species.
|
|||||||||||||||||||||||||
| Question 1. What is the kingdom of the great white shark? A. Plantae B. Animalia C.Eubacteria 2. What age male white shark reach sexual maturity? A. 20 years B. 26 years C. 33 years 3. What age female white shark reach sexual maturity? A. 25 years B. 30 years C. 33 years 4. What is the newest maximum lifespan of white shark? A. 45 years B. 50 years C. 70 years 5. Shark is..... A. Viviparous B. Ovoviparous C. Ovoviviparous |
|||||||||||||||||||||||||
Komentar
Posting Komentar