Three paleontologists speculate about what sorts of kosher food would be available to a Jewish time-traveler to the prehistoric era, before such modern species as cattle and chicken existed. Roy Plotnick, Jessica Theodor, and Thomas Holtz write:
The first stop is 120,000 years ago. This was the peak of the last interglacial warm period before the most recent ice age and before humans first reached the New World or Australia. It was thus prior to the extinction event that wiped out many of the large animals in the world, such as mammoths and giant ground sloths. Many of these extinct animals are either ancestral to or related to animals that we would recognize as kosher. In Eurasia, we would find the aurochs, Bos primigenius, the ancestor of today’s domestic cattle, which went extinct in the 15th century, and the giant Irish elk, the largest deer of all time. There would also have been the wild ancestors of modern fowl, sheep, and goats. In the Americas we would be able to feast on abundant ancestral bison, as well as a variety of deer, pronghorns, and turkey. Acceptable fish would be found in fresh and marine waters throughout the world.
Going back further in time, the scientists determine that, despite the relationship between birds and dinosaurs, pterodactyls are not kosher.
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