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mammal: Quick Facts

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News •

The mystery of how hair knows where to grow may finally be solved • Nov. 11, 2026, 8:27 AM ET (Science Daily)
Scientists discovered a tiny furry predator from 165 million years ago that hunted slippery prey in the water • Nov. 8, 2026, 7:11 AM ET (Earth.com)
Crows can evaluate visual info twice as fast as mammals • Oct. 23, 2026, 1:32 PM ET (Ars Technica)

Facts

Also Known As Mammalia

Photos and Videos

polar bear and cubs
okapi
World map displaying faunal realms and major animal regions, with color-coded areas representing the Holarctic, Paleotropical (Afro-Tethyan), Neogaean (Neotropical), Notogaean (Australian), and Oceanic realms. Major boundaries and notable regions such as Afrotropical, Oriental, Madagascan, Wallacea, Australian, and Hawaiian are labeled, and arrows indicate the hypothesized distribution of Antarctic fauna.
Goat herding
An illustration of Steller's sea cows (Hydrodamalis gigas) swimming and feeding on kelp near the shore, with two people in traditional clothing observing from a wooden boat above the water.
Bottlenose dolphins
Diagram of the human female reproductive system showing the journey of an egg from the ovary through the fallopian tube, including fertilization by sperm, cell divisions from one to eight cells, and implantation of the blastocyst in the uterus.
Cross-sectional medical illustration of a human uterus at seven weeks of pregnancy, showing the developing embryo inside the amniotic sac, placenta, umbilical cord, uterine wall layers, cervix, and vagina, with labeled anatomical structures related to gestation and embryology.
leopard
Yellowstone wolf pack
Small squirrel peeking out of a snowy bank, with a blue circle surrounding it.
Collage showing a dog plus a saber-toothed cat equaling a prehistoric, quadrupedal creature with thick limbs and dark, hairless skin.
Which mammals have the shortest and longest gestations
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Related Topics and References

Topics
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Key People

Karl Ernst von Baer
Karl Ernst von Baer
Prussian-Estonian embryologist
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George Gaylord Simpson
American paleontologist
William Henry Flower
William Henry Flower
British zoologist
Purkinje, Jan Evangelista
Jan Evangelista Purkinje
Czech physiologist
Voit, Carl von
Carl von Voit
German physiologist
Baird, Spencer Fullerton
Spencer Fullerton Baird
American naturalist
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Steen Willadsen
Danish embryologist
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Geoffrey Bourne
American anatomist
William Diller Matthew
William Diller Matthew
Canadian-American paleontologist
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Reginald Innes Pocock
English zoologist
Reinier de Graaf, engraving by an unknown artist
Reinier de Graaf
Dutch physician
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John Bachman
American naturalist and minister

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The bearded vulture (Gypaetus barbatus) is seen in Switzerland on December 2024
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Sea otter (Enhydra lutris), also called great sea otter, rare, completely marine otter of the northern Pacific, usually found in kelp beds. Floats on back. Looks like sea otter laughing. saltwater otters
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