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hammerhead shark

(Encyclopedia)hammerhead shark, active, surface-living shark, genus Sphyrina. Its curious head has lateral projections resembling the crossbar of a T, and its eyes and ears are located in the outer tips of the proj...

Freetown

(Encyclopedia)Freetown, city (1995 est. pop. 519,500), capital of Sierra Leone, W Sierra Leone, a port on the Atlantic Ocean. Located on the Sierra Leone peninsula, Freetown is the nation's administrative, communic...

gull

(Encyclopedia)gull, common name for an aquatic bird of the family Laridae, which also includes the tern and the jaeger. It is found near all oceans and many inland waters. Gulls are larger and bulkier than terns, a...

fossa

(Encyclopedia)fossa, carnivorous mammal, Cryptoprocta ferox, of Madagascar. The island's largest carnivore, the fossa resembles a puma in appearance and has semiretractable claws, but it is most closely related to ...

echo sounder

(Encyclopedia)echo sounder, an older instrumentation system for indirectly determining ocean floor depth. Echo sounding is based on the principle that water is an excellent medium for the transmission of sound wave...

defoliant

(Encyclopedia)defoliant, any one of several chemical compounds that, when applied to plants, can alter their metabolism, causing the leaves to drop off. In agriculture defoliants are used to eliminate the leaves of...

eutrophication

(Encyclopedia)eutrophication yo͞otrōˌfĭkāˈshən [key], aging of a lake by biological enrichment of its water. In a young lake the water is cold and clear, supporting little life. With time, streams draining i...

snapping turtle

(Encyclopedia)snapping turtle, large, aggressive New World freshwater turtle. The two snapping turtle species are the sole members of the family Chelydridae. Snapping turtles prefer quiet, muddy water. They spend m...

Bakassi

(Encyclopedia)Bakassi bäkäˈsē [key], peninsula, c.400 sq mi (1,000 sq km), E Cameroon, on the Cameroon-Nigeria border, at the SE end of the Gulf of Guinea. The swampy peninsula and associated small islands are ...

porpoise

(Encyclopedia)porpoise, small whale of the family Phocaenidae, allied to the dolphin. Porpoises, like other whales, are mammals; they are warm-blooded, breathe air, and give birth to live young, which they suckle w...