Here’s what you’ll learn when you read this story:The oldest surviving proteins have been found in the tooth of Elasmotherium, a prehistoric rhino with one unicorn-esque horn. These protein sequences are 20 million years old—far older than the previous oldest sequences, from mammoth (1.2 million year old) and camel ancestors (3.7 million years old), respectively. Elasmotherium was found to be closely related to ancient rhino lineages from Eurasia, even though the tooth was found in Canada. Most ancient DNA (aDNA) over 1 million years old is far too fragmented to reconstruct genetic sequences. The York team focused on extracting proteins and amino acids from the enamel of the tooth, since the tightly packed substance protects genetic material.