Mammals first appear in the fossil record of the Mesozoic Era.
mammals
The Mesozoic Era
Mesozoic(:
The answer is Cenozoic in the beginning of this era there were few mammals and birds but longer down the road more animals appeared as the era continued.And so my answer would be Cenozoic but i am not completely sure.:(ANSWER ABOVE IS INCORRECTMesozoic is the correct answer small mammals evolved during the Mesozoic era, with reptiles, as did birds. The full potential and releasing of mammals came in the Cenozoic, when the mass extinction of 20% of the Mesozoic's species happened.
probably mesozoic era
The current era is the "great age of mammals," the Cenozoic. The Mesozoic was the age of dinosaurs.
the first type of life form that appeared in the mesozoic era was a fish! the second type of life form that appeared in the mesozoic era was the reptile! and the third was a reptile bird!!!!!!!!!!!!!!!!
The first dinosaurs lived in the beginning of the Mesozoic Era (or the Age of Reptiles). Birds were amazingly discovered to be dinosaurs so dinosaurs were also alive in the Cenozoic (that's our time-the Age of Mammals) to today.
"Age of the dinosaurs" is a common nickname for the Mesozoic Era because it was a period when dinosaurs dominated the Earth.
dinosaurs. as well as small mammals (rodents) and amphibians
Mammals and dinosaurs emerged in the Mesozoic era. Plants appeared in the Paleozoic era, which came before it.