Remains of a baby woolly rhino that roamed the planet nearly 10,000 years ago were uncovered in a frozen riverbank in Siberia, researchers told NBC News. The rhino baby, presumed to be between 3 and 4 years old, is the only complete young specimen of the extinct species ever found, according to scientists at the Yakutian Academy of Sciences in Russia. The remains were donated to the academy for study as researchers hope to extract DNA to determine its mammal family tree placement. Since the 18th century, remains of only a few adult woolly rhinos have been discovered, including two complete bodies without hair and one headless, frozen mummy. Woolly rhinos first appeared nearly 350,000 years ago and went extinct about 10,000 years ago.