mammal

noun mam·mal \ ˈma-məl \

Updated on: 15 Apr 2018

Definition of mammal

: any of a class (Mammalia) of warm-blooded higher vertebrates (such as placentals, marsupials, or monotremes) that nourish their young with milk secreted by mammary glands, have the skin usually more or less covered with hair, and include humans

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mammalian

play \mə-ˈmā-lē-ən, ma-\ adjective or noun

See mammal defined for English-language learners

See mammal defined for kids

Examples of mammal in a Sentence

Human beings, dogs, and cats are all mammals.

Recent Examples of mammal from the Web

Leeches, the researchers reported in the journal Systematics and Biodiversity, are far from picky eaters: the parasites had fed on 26 different mammal species, plus three birds.

— rachel nuwer, New York Times, "It’s the Latest in Conservation Tech. And It Wants to Suck Your Blood.," 9 Apr. 2018
Since RNA viruses cause a wide range of diseases in people and livestock, researchers have mostly studied the ones that infect mammals and birds.

— giorgia guglielmi, Scientific American, "Huge Trove of Unknown Viruses Found in Fish, Frogs and Reptiles," 5 Apr. 2018
Researchers looked at 3,859 living and 2,999 fossil mammal species to figure that out.

— sara sneath, NOLA.com, "Why are marine mammals so big? Louisiana experts answer," 3 Apr. 2018
The whales are one of the rarest marine mammals in the world, numbering about 450.

— patrick whittle, The Christian Science Monitor, "As right whales face extinction, activists buoy hope," 3 Apr. 2018
At this point in the Paleocene period, dinosaurs were extinct, mammals and birds began to evolve and the Earth was filled with dense forests.

— julissa treviño, Smithsonian, "Britain’s Prehistoric Coastline Uncovered in West London," 19 Mar. 2018
Soon a buildup of marine mammal and avian excrement started to waft through the neighborhood.

— author: jason bittel, Anchorage Daily News, "Sea lions have made a magnificent comeback, and they want their beaches back," 20 Feb. 2018
Pronghorn hit speeds faster than any other mammal in North America, so once an animal was secured, several hands lifted its hooves off the ground.

— alex devoid, azcentral, "Back from the brink, the Sonoran pronghorn now roam an increasingly political landscape," 27 Mar. 2018
Right now, studies on diabetes in non-humans tend to focus on other mammals—and even then the results don’t always neatly transfer to humans.

— cathleen o'grady, Ars Technica, "Blind cavefish seem to ignore insulin without health consequences," 23 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'mammal.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of mammal

New Latin Mammalia, from Late Latin, neuter plural of mammalis of the breast, from Latin mamma breast

NEW! Time Traveler

First Known Use: 1813

See Words from the same year

Other Mammals Terms

dormouse, dugong, gibbon, grimalkin, sable, stoat, ungulate, vole

MAMMAL Defined for English Language Learners

mammal

noun

Definition of mammal for English Language Learners

: a type of animal that feeds milk to its young and that usually has hair or fur covering most of its skin

MAMMAL Defined for Kids

mammal

noun mam·mal \ ˈma-məl \

Definition of mammal for Students

: a warm-blooded animal (as a dog, mouse, bear, whale, or human being) with a backbone that feeds its young with milk produced by the mother and has skin usually more or less covered with hair