Definition

1. Proper noun (Geological time period):
   • The Cenozoic Era: The geological era spanning from approximately 66 million years ago to the present, characterized by the rise to dominance of mammals following the extinction of the dinosaurs.

Usage

• The term "Age of Mammals" is used as a proper noun to refer to a specific, defined span of geological history. It is typically capitalized when used formally.
• It is used in scientific, educational, and general contexts to describe the current era in Earth's history.

Examples

Advanced Usage

• The phrase can be used metaphorically to emphasize the prominence or dominance of mammals in a given context.
  • With humans shaping the planet's ecology, some argue we have entered a new Age of Mammals driven by technology.

Variants and Related Words

• Cenozoic Era: The formal scientific name for the Age of Mammals.
• Age of Reptiles: A common name for the preceding Mesozoic Era.
• Mammalian: (Adjective) Relating to mammals.
• Tertiary and Quaternary: These are outdated formal subdivisions of the Cenozoic Era.

Synonyms

• Cenozoic Era (scientific synonym)
• Kainozoic Era (an alternative spelling)

Notes on Meaning

• The "Age of Mammals" is not a precise chronological date but a broad era encompassing multiple epochs (e.g., Paleogene, Neogene, Quaternary).
• It specifically highlights the biological dominance of the class Mammalia, even though other life forms (birds, insects, plants) also evolved significantly during this time.

Noun

1. approximately the last 63 million years