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mayfly

(Encyclopedia)mayfly, any insect of the order Ephemeroptera, so named because the adults live for a short time, often only a single day, during which they molt twice, mate, and lay their eggs in freshwater. The adu...

water beetle

(Encyclopedia)water beetle, name for aquatic beetles of several families. They should not be confused with water bugs, which are true bugs (order Hemiptera). The predaceous diving beetles (family Dytiscidae) are a ...

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...

Rotifera

(Encyclopedia)Rotifera, phylum of predominantly free-living, microscopic, aquatic or semiterrestrial pseudocoelomates. Each rotifer has a head bearing a crown of cilia, the corona, at the anterior end; most rotifer...

hyena

(Encyclopedia)hyena hī-ēˈnə [key], carnivorous, chiefly nocturnal mammal of the Old World family Hyaenidae. Although doglike in appearance, hyenas are more closely related to civets (family Viverridae) and cats...

polecat

(Encyclopedia)polecat, carnivorous mammal of the weasel family. The name refers especially to the common Old World polecat, Mustela putorius, found in wooded areas of N Eurasia and N Africa. Similar to weasels, but...

beaver

(Encyclopedia)beaver, either of two large aquatic rodents, Castor fiber and Castor canadensis, known for their engineering feats. They were once widespread in N and central Eurasia except E Siberia, and in North Am...

Chordata

(Encyclopedia)CE5 Common features in representative groups of the phylum Chordata Chordata kôrdāˈtə, –däˈ– [key], phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal ...

seal, in zoology

(Encyclopedia)seal, carnivorous aquatic mammal with front and hind feet modified as flippers, or fin-feet. The name seal is sometimes applied broadly to any of the fin-footed mammals, or pinnipeds, including the wa...

dragonfly

(Encyclopedia)dragonfly, any insect of the order Odonata, which also includes the damselfly. Members of this order are generally large predatory insects and characteristically have chewing mouthparts and four membr...