Peter Simon Pallas (September 22, 1741 - September 8, 1811) was a German-born Russian zoologist.
Pallas was born at Berlin, the son of a Professor of Surgery. He studied with private tutors and took an interest in natural history, later attending the University of Halle and the University of Göttingen. In 1760 he moved to the University of Leiden and passed his doctor's degree at the age of nineteen.
He travelled throughout the Netherlands and to London, improving his medical and surgical knowledge. He then settled at The Hague, and his new system of animal classification was praised by Cuvier. He wrote Miscellania Zoologica (1766), which included the descriptions of several vertebrates new to science which he had discovered in the Dutch museum collections. A planned voyage to southern Africa and the East Indies fell through when his father recalled him to Berlin. Here he began work on his Spicilegia Zoologica (1767-80).
In 1767 Pallas was invited by Catherine II of Russia to became a professor at the St Petersburg Academy of Sciences, and between 1769 and 1774 he led an expedition to Siberia collecting natural history specimens on their behalf. He explored the upper Amur, the Caspian Sea, and the Ural and Altai mountains, reaching as far eastward as Lake Baikal.
Between 1793 and 1794 he led a second expedition to southern Russia, visiting the Crimea and the Black Sea.
In 1772 Pallas was shown a 700 kilogram lump of metal which had been found near to the city of Krasnoyarsk. Pallas arranged for it to be transported back to St Petersburg. Subsequent analysis of the metal showed that it was a new type of stony-iron meteorite. This new type of meteorites are called Pallasites after him whereas the meteorite itself is today named Krasnoyarsk or sometimes also called Pallas Iron (the name given to it by Ernst Chladni in 1794).
A number of animals are named after him, including Pallas's Cat, Pallas's Warbler, Pallas's Gull, Pallas's Sandgrouse and Pallas's Reed Bunting.