Page 70 - World of Animals - Deadly Predators

Deadliest catch

Intelligent sea creatures that use every part of their

bodies as powerful weapons

Sharks have barely changed since their evolution over It isn’t a myth that sharks can smell blood. When a
400 million years ago. Their skeletons are made of mammal sniffs the air, scent molecules dissolve in the
lightweight, flexible cartilage rather than dense bone, wet lining of the nose. The process is just as efficient
and being free of heavy skeletal structures means in water, and some sharks can detect odours at one
that the fish can swim faster and move with increased part per 10 billion. Sharks have two nasal cavities called
agility. This isn’t a case of sharks having primitive nares, with each one having a separate entrance and
bones – evidence suggests that they developed light exit and leading to a convoluted network of skin folds
skeletons after evolving from animals with much coated with scent detectors. Some sharks dedicate
heavier calcium bones. Sharks emerged as next- two-thirds of their brains to deciphering odours,
generation hunters that had an advantage over other suggesting smell is their most important sense.
predators in the sea, and the formula was so lethally Sharks perceive the world with senses humans don’t
effective that they still exist in almost exactly the same have. The ampullae of Lorenzini are pores on a shark’s
configuration today. face that pick up electrical signals. Each is filled with
These fish are famous for their teeth, which work a jelly-like substance that conducts electricity. The
like a conveyer belt, moving forwards to replace ones base is covered with hair-like structures that react to
that have been lost in battle. Lemon sharks have the changes in electrical currents. Hammerhead sharks
sharpest teeth and generally target small prey like have an elongated face covered with 3,000 of these
stingrays and seabirds. Their teeth aren’t triangular like pores. They scan the seabed, swimming slowly and
the typical shark tooth, but instead stick straight up low to the sand. Muscles of prey under the sediment
away from the gum bed like miniature daggers. The generate electric impulses and a hammerhead can
narrow tooth tip has a tiny surface area, which means locate a buried fish like a metal detector.
THRESHER SHARK
the jaws are supercharged with enormous pressure. Lateral lines are another way sharks collect Alopias vulpinus
A lemon shark disturbs the sand on the seabed to information. A long groove of sensory cells runs down Lifespan 8-13 years
cloak its outline before appearing through the cloud of Adult weight 230kg (510lbs)
Conservation status
silt. When searching for flying prey, it breaks through Thresher sharks
the surface of the sea and grabs an unlucky bird at have extremely long
tails and use them
breakneck speed. to whip prey into VULNERABLE
Even the fastest of prey has little chance against a submission
shark. Shark speed is driven by a number of factors;
their body shape is perfectly streamlined like a
torpedo, and their rough skin helps reduce water
resistance when swimming at speed. Their fins are
placed strategically to maintain balance and keep them
moving through the water automatically. The muscles
that run through a lemon shark lie close to the spine
to help keep the tail under control, and the tail itself
is considered to be the shark’s engine, surrounded by © Getty
muscle and asymmetric in shape. The upper section
grows far longer than the lower half, making it more
manoeuvrable as a result.

Hammerheads can sense
the Earth’s magnetic field
WHALE SHARK
Rhincodon typus and actively follow it when
swimming in schools
Lifespan 70-100 years
Adult weight 19,000kg
(42,000lbs)
Conservation status

Whale sharks
are the biggest ENDANGERED
fish alive
and though
technically
carnivores, they
are slow-moving
filter-feeders

© Thinkstock © Thinkstock

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