: 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
mammal-like
adjective
or less commonly mammallike
mammal-like behavior
mammallike reptiles
Examples of mammal in a Sentence
Human beings, dogs, and cats are all mammals.
Recent Examples on the Web
More than 80 domestic cats, among many other types of mammals, have been confirmed to have had bird flu since 2022 -- generally barn cats that lived on dairy farms, as well as feral cats and pets that spend time outdoors and likely caught it by hunting diseased rodents or wild birds.
—
Sarah Boden, ABC News, 10 Feb. 2025
Gene sequencing of these D1.1 viruses has found a mutation that helps the virus copy itself more efficiently into the cells of mammals, including people.
—Brenda Goodman, CNN, 8 Feb. 2025
Wille and a team of other wildlife experts estimate that millions of birds have been infected and died, and tens of thousands of marine mammals have died.
—Gabrielle Emanuel, NPR, 7 Feb. 2025
There are also some non-native mammals that were introduced to North America that are considered a major problem.
—Stan Tekiela, Twin Cities, 6 Feb. 2025
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Sarah Boden, ABC News, 10 Feb. 2025
Gene sequencing of these D1.1 viruses has found a mutation that helps the virus copy itself more efficiently into the cells of mammals, including people.
—Brenda Goodman, CNN, 8 Feb. 2025
Wille and a team of other wildlife experts estimate that millions of birds have been infected and died, and tens of thousands of marine mammals have died.
—Gabrielle Emanuel, NPR, 7 Feb. 2025
There are also some non-native mammals that were introduced to North America that are considered a major problem.
—Stan Tekiela, Twin Cities, 6 Feb. 2025
See all Example Sentences for mammal
Dictionary Entries Near mammal
Cite this Entry
“Mammal.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mammal. Accessed 21 Feb. 2025.
Copy CitationKids Definition
mammal
noun
mam·mal
ˈmam-əl 
: any of a class of warm-blooded vertebrates that include human beings and all other animals that nourish their young with milk produced by mammary glands and have the skin usually more or less covered with hair
Medical Definition
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