One population of mammoths lived on in isolation on Russia's remote Wrangel Island until about 5, 000 years ago.

BBC: The mammoth's trunk and eyes are still intact

For my last zapovednik evening, another ranger, Kolya Solovev, invited our half-a-dozen-strong geyser valley community to his cabin to dine on smoked salmon and watch a slideshow of polar bear and musk oxen, whose company Solovev enjoyed the year before when rangering at the Arctic zapovednik that protects all of Wrangel Island.

BBC: Five days in Russia's Ring of Fire