Fossil ivory hunters who found a well-preserved bird carcass in northeastern Siberia thought it was only a day or so old.
Turns out, it was about 46,000 years old.
The unusual bird carcass was discovered in permafrost near the village of Belaya Gora.
Scientists at the Swedish Museum of Natural History determined that the Ice Age specimen was a horned lark, according to a paper recently published in Communications Biology.
"The fact that such a small and fragile specimen was near intact also suggests that dirt/mud must have been deposited gradually, or at least that the ground was relatively stable so that the bird's carcass was preserved in a state very close to its time of death," Love Dalén, one of the scientists behind the discovery, told CNN.
Researchers believe the frozen bird, discovered in 2018, is an ancient ancestor of two lark subspecies that are still in existence today. As scientists determine more of the bird's genome, they can determine the evolutionary rate of the species.
The horned lark from the Pleistocene era isn't the only frozen animal discovered at the Siberian site. Scientists have found remains of mammoths, wooly rhinos, and even an 18,000-year-old frozen puppy.
Workers continue to uncover all of the frozen history in the Siberian village, with hopes of painting a clearer picture of the effects of climate change over the past century.