early mammals
Ancient warm-blooded ancestors
Early mammals refers to the first mammals that evolved during the Mesozoic Era, when dinosaurs dominated.
These were generally small, nocturnal creatures—often shrew-like or rodent-sized—that diversified rapidly after the dinosaurs' extinction.
The term appears in paleontology and evolutionary biology: Early mammals filled ecological niches unavailable to larger animals.
- fossilsPreserved ancient organism traces
- Triassic periodFirst Mesozoic geological span
- nocturnalActive during darkness
- Jurassic periodGeologic age of dinosaurs
- MesozoicAge of Reptiles
placental · insectivore · Cretaceous period · monotremes · warm-blooded · body heat · milk · live birth · burrows · extinct · paleontology · tiny · small size · skulls · teeth · soft bodies · marsupials · eggs
- prehistoric lifedinosaur, dinosaurs, triceratops, Velociraptor, velociraptor
- mammal evolutionfossil record, diversification, human evolution, Australopithecus, Homo erectus
- Early Jurassicichthyosaurs, ammonites, Dilophosaurus, marine fossils
- Mesozoicdinosaurs, Velociraptor, Brachiosaurus, Spinosaurus, pterosaurs
- extinct creaturesdinosaurs, trilobites, ammonites, mammoths, pterosaurs
- fossilsdinosaur bones, ammonite, amber, ammonites, fossils
early mammalsdinosaurs
Extinct prehistoric reptiles
reptiles · archosaurs · pterosaurs · birds · amphibians
early mammalsmegafauna
Species over 44 kilograms
apex predators · dominant species · placental mammals · keystone species
early mammalsapex predators
Dominant hunters, no natural enemies