The Pleistocene is a geological epoch that lasted from about 2.6 million to 11,700 years ago. It is characterized by fluctuating global temperatures and repeated glaciations, which had significant impacts on the Earth's climate and ecosystems. The Pleistocene is known for the presence of large mammals such as mammoths, sabertooth cats, and giant ground sloths, as well as early human species like Homo erectus and Homo neanderthalensis. Research on the Pleistocene often focuses on understanding past climate changes, the evolution of plants and animals, and the interactions between early humans and their environment.