Page 57 - World of Animals - Book of Sharks & Ocean Predators

Hammerhead sharks
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Electroreception

The face is covered with tiny black spots called the

ampullae of Lorenzini, which “detect electric fields in the
water” according to Fessler. They’re open pores fi lled
with electrically conductive material.
“The ampullae contain a jelly-like substance
which vibrates when an electrical signal is
detected.” The base of the pore is covered
with tiny hair-like cilia, which respond to
changes in electrical currents. Just like the hairs
in a human ear detect the direction and volume of
sound, the shark’s cilia can distinguish tiny changes in
electric currents.
“The ampullae can pick up electrical signals from
muscle contractions of prey,” he continues. A great
hammerhead shark has over 3000 receptive
pores, making them masters
In low light a
of electroreception. hammerhead
shark can see 10
times better than
a human could

Teeth
The sharp serrated
teeth of a hammerhead
are constantly growing to replace
any that become embedded in
prey, and new teeth move forward
like a deadly conveyer belt.
360° vision

Hammerhead sharks have brilliant “Hammerhead sharks eyes are spaced
360-degree vision. “Shark vision is very so far apart, they have larger blind spots
good,” explains Fessler. “They are able in front of them than other sharks”
to scan over 180 degrees with a single continues Fessler. Behind the retina are
eye, which means the visual fi elds of mirrored crystals called the tapetum
both eyes overlap”. This wide spacing lucidum, and when light hits this layer of
of the eyes comes at a cost, however. crystals it is reflected several times.

Inside a shark’s eye Tapetum

A layer of crystals reflects light
Sharks have an extra layer at the back of their towards the rods and cones to
eyes that helps with night vision assisit with low light conditions

Fins Cornea

The dorsal and pectoral fins of the shark slice Light enters
through the water acting as natural rudders and though the
stop the hammerhead from rolling sideways or cornea
pitching forwards when in pursuit of prey.

Face Light
The hammerhead’s wide T-shaped face
helps it turn quickly in the water, and
the large surface area is packed with Rods and cones Retina skin
electroreceptors, making it the most Light sensitive cells send
successful detector of electric currents. signals to the brain

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