Sharks
Sharks are
a clutch of elasmobranch fish determined by their cartilaginous skeleton as
they have no bones in their whole body. Sharks normally have gill cuts on the sideways
of their head as on all other fishes.
Scientific
name: Selachimorpha
Subclass : Elasmobranchii
Clade : Neoselachii
Domain : Eukaryota
Kingdom : Animalia
Phylum : Chordata
Lifespan : 20-30
years
The first sign
for the existence of sharks which is a fossil is a few scales dating to 450
million years. Some other species of
sharks can live lengthier up to 200 years or more.Body shape: Sharks frequently
have a fusiform body which means that their body is rounded and conical on the
both tops. This lean form of their body comforts them in swimming by dropping
drag and due to this a lowest expanse of energy is involve to swim.
In addition
to this their body is of dull gray colour and also has tooth like scales alike
all other fishes. Sharks have no swim bladders it is an interesting and odd
thing about sharks that’s why they have to swim uninterruptedly to keep from dipping.
That is the objective that all sharks are marginally negatively floating it
means they sink. Mostly sharks are ectothermic which means that sharks match
their body temperature with the water nearby them. Purely we can say that
sharks are cold blooded.
Reproduction:
Some shark
species reach to their maturity at the age of 20 year. Sharks take decades to
mature. Sharks have internal fertilization which means that fertilization
occurs in the body of sharks. The male reproductive organ which is known as
clasper is inserted into the female body for the addition of male gametes. In opposition
to this other fish species have to lay eggs and later on the male fertilized
those eggs externally.
Mostly
sharks give birth to their young ones. As opposed to the other fish species
that mostly lay eggs. Gestation period of sharks vary from 11-12 months which
means sharks give birth to their young ones after that long period of
pregnancy. In addition to this the gestation period of some sharks is long like
the pregnancy of frilled shark is of 3 years. Some shark species also lay eggs
like many other fish species those are wobbegongs, horn sharks and some other
cat sharks.
Mode of nutrition:
Sharks are carnivores
which mean that sharks feed on meat of other fish and sea mammals. In addition
to this, sharks can also eat sea turtles, seagulls, dolphins, seals and other
sharks. Sharks have strong numerous rows of strong teeth that are continuously replaced
in their whole life.
So, it is not a problem for a shark to chew the hard
shells of turtles. Sharks mostly have three meals per day. Mostly sharks have
good eyesight which helps them to get their prey. And in addition to this
sharks also have some special electroreceptor organs which also help them. Sharks
also have six senses that are sight, hearing, smell, taste and touch. In
addition to this sharks also have lateral lines. An interesting thing about
sharks is that they don’t pee. As their urine is absorbed by their own body it
is necessary for the sharks because their waste contains urea which stops
losing water form their body.
Types:
There are
almost five hundred species of sharks present in oceans. And these species are
divided into eight orders which are Carcharhiniformes, Hederodotiformes,
Hexanchiforms, Lamniformes, Orectolobiformes, Pristiophoriformes, Squaliformes,
and Squatiniformes. All of them have their own behavior.
There are some types
of sharks:
- Blacknose
shark Blacktip
shark
- Blue shark Brown
shark
- Blacktip
reef shark Bull
shark
- Caribbean
reef shark Bronze
whaler shark
- Dusky shark Galapagos
shark
- Great
hammerhead shark Grey
reef shark
- Lemon shark Leopard
shark
- Oceanic
whitetip shark Pacific
sharpnose shark
- Pyjama
shark Sand
tiger shark
- Scalloped
hammerhead shark Sharptooth
lemon shark
- Silky shark Silvertip
shark
- Smooth
hammerhead shark Smoothhound
shark
- Spinner
shark Tiger
shark
- Horn shark Bluntnose
sixgill shark
- Broadnose
sevengill shark Frilled
shark
- Sharpnose
sevengill shark Basking
shark
- Bigeye
thresher shark Crocodile
shark
- Goblin
shark Longfin
mako shark
- Megamouth
shark Porbeagle
shark
- Salmon
shark Shortfin
mako shark
- White shark Bluegrey
carpet shark
- Epaulette
shark Nurse
shark
- Spotted
wobbegong Tawny
nurse shark
- Whale shark Whitespotted
bamboo shark
- Zebra shark Bahamas
sawshark
- Bramble
shark Cookiecutter
shark
- Great
lanternshark Greenland
shark
- Gulper
shark Kitefin
shark
- Pacific
sleeper shark Pygmy
shark
- Spiny
dogfish Angel
shark
- Common
thresher shark Port
Jackson shark
- Requiem
shark Copper
shark
All these
are the some common types of sharks and all these species have their own behavior
and characteristics. As we know that Greenland sharks can live longer than many
other species and in the same way horn sharks lay eggs instead of giving birth
to their young ones as many other shark species do. And in the same way the
great white shark is considered as the most dangerous shark in the world. Tiger
shark and Bull shark are also present in the top deadliest shark list.
And if we
talk about beauty than the whale sharks are on the top of the list. White
shark, Greenland shark, Tiger shark also follow them.
Interesting facts:
Here are the some interesting facts about sharks:· Sharks do not have bones. As their skeleton is completely made up of bones.· Most species of sharks have good eyesight which helps them to see well in the dark areas.· Sharks skin feels like sandpaper. Due to placoid scales sharks can swim better.· Blue sharks are really blue. In opposite to that mostly sharks have dull grey skill.· Different shark’s species reproduce in different ways. As some species of sharks lay eggs and some give birth to their young ones.
· Spot pattern of whale shark is as unique as a fingerprint. As every whale individual of the species has his own unique pattern of spots.
· Some shark species have to keep swimming during rest.
While some species have spiracle which pulls water in their respiratory track
while at rest.
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