What lifeforms characterize the Quaternary period?
The Quaternary Period is characterized by mammals, particularly humans.
The Quaternary period runs from 2.6 million years ago to present time and one of the prevalent lifeforms was and continues to be mammals. This period was full of what are called megafauna and megaflora, such as the mastodon and the wooly mammoth. This period is sometimes referred to as "The Age of Humans" since it is when our own species evolved.