Learn all the Terminology About Sharks with our Shark Glossary

Our shark glossary covers some of the terms used on this site that you may not have come across before.

A

Adelphophagy – Intrauterine cannibalism, the act of eating the siblings in the womb.

Ampullae of Lorenzini – These are tiny dents in the head and snout that detect electrical fields

Anal Fin – The fin on the underside of some sharks. Situated between the pelvic fins and the caudal fin.

B

Barbels – Long whisker-like organs found near the mouths of some species. They help to locate food in poor visibility.

Benthic – The seabed, or the bottom of a lake or stream. Benthic sharks are bottom dwellers.

Bioluminescence – Light produced by living organisms, including some sharks. eg. Lantern shark.

Branchial – Related to gills.

C

Caudal Fin – The tail fin.

Caudal Keel - A ridge found on the caudal peduncle of some sharks which provides stability during fast movement through the water.

Caudal Peduncle - The narrow part of the shark to which the tail fin is attached - the tail stalk.

Chondrichthyes – Cartilaginous fish.

Claspers – The two rolls of cartilage found near the pelvic fins of sexually mature male sharks. They serve to guide the sperm into the female’s cloaca during mating.

Cloaca – Opening for excretion of body waste and for reproduction.

Countershading - Having a lighter colour on the underside than on the upper side. This helps with camouflage from both above and below.

D

Dermal Denticles – Tiny tooth-like scales on the skin of a shark. Also called placoid scales.

Dorsal Fin – The fin(s) on the upper side of the shark. Some have only one while others have two.

E

Ectotherm – An animal whose body temperature is determined by its surroundings. Most sharks are ectothermic.

Elasmobranchii – The sub-class of the class Chondrichthyes that sharks, rays and skates belong to.

Endotherm – An animal able to generate its own body heat and maintain a constant temperature regardless of its surroundings.

G

Gill – The organ that allows aquatic animals extract oxygen dissolved in water.

Gill Slits - Most sharks have five gill slits on both sides of their heads from which water exits after being drawn in through the mouth and over the gills.

Gill Rakers – Stiff projections protruding from the gill arches of filter feeders that prevent tiny food particles passing through.

H

Heterocercal – A caudal fin with unequal sized lobes.

Homocercal – A caudal fin with equal sized lobes.

I

Inter-Dorsal Ridge - A ridge of skin between the first and second dorsal fins of some sharks

L

Lateral Line – A row of sense organs found down the side of the body that detect movement in the water.

M

Myomeres – Muscles found along the flanks which aid in swimming.

O

Osmoregulation – The control of water concentration in the body.

Oviparous – Egg laying animals where little or no embryonic development occurs inside the mother’s body.

Ovovivparous – The young develop in eggs and nourished by yolk, but the eggs are kept within the mother’s body until they’re ready to hatch.

P

Pectoral Fins – The pair of fins set low on the body and towards the front.

Pelagic – Relating to open water. Pelagic sharks are found in the open ocean.

Pelvic Fins – The pair of fins set low on, and to the rear of the body.

Placoid Scales - Also called dermal denticles. Small tooth-like scales on the skin of a shark

Plankton – Microscopic animals (zooplankton) and plants (phytoplankton) found floating in the marine environment and eaten by filter feeders.

R

Ram Filtration - A method of filter feeding where the shark swims forward with a wide open mouth to force water in and over the gills.

Ram Ventilation - A method of breathing where the shark must keep swimming forwards in order to keep oxygenated water flowing over the gills.

Rostrum - The long, saw-like snout of the saw sharks and sawfishes.

S

Spiracle – Opening behind the eye in some sharks which directs oxygen to the eye and brain, and aids water flow over the gills.

Squalene – Contained in the oil found in shark’s liver.

T

Teleost - Bony fish.

Tonic Immobility - A state of paralysis that can be induced by turning a shark on its back.

V

Viviparous – A reproduction mode where the embryo develops inside the mother’s body.

We will be adding to our shark glossary as the website grows.

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