What Could a Jewish Time Traveler Eat?
Sometimes, the most elucidating questions are the most outlandish. Take, for example, the one posed by Roy Plotnick, Jessica Theodor, and Thomas Holtz in a September publication of the journal Evolution: Education and Outreach:
Horrible puns aside, the question is an intriguing one. If a devout Jew, keeping Kosher, were to travel back in time, what exactly would they be able to eat?
The Jewish holy book, the Torah, permits the consumption of select animals. Only land animals that both "chew the cud" and have cloven hooves are allowed. That means ruminants like cows are on the menu, while pigs are not. Fish with both fins and scales are also permitted. Birds of prey are not to be eaten, along with "creeping things" that crawl the earth and "flying creeping things" (commonly taken to mean "insects" and "flying insects"). However, grasshoppers, beetles, and certain types of locusts are permitted.
But, of course, the animals around today aren't the same as they were thousands or millions of years ago. The kosher animals of today may not have been around in the ancient past!
So what was? The authors explored numerous eras in a literary piece of time travel. Their first stop was 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... 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.
So a pretty decent selection for our theoretical Jewish time traveler! But what if we venture farther back, say, 52 million years, to the shores of Fossil Lake in what is now Wyoming?
The lake teems with kosher fish, including abundant perch, herrings, and bass. Crickets chirp along the shore. There are also abundant modern-looking birds including relatives of modern land and water fowl. Mammals are present, but the Ruminantia have yet to appear on Earth. Thus it would seem that an observant Jew would be limited to a non-mammalian diet, consuming only fishes, birds, and orthopterans (grasshoppers and crickets).
The number of choices is dwindling, but it's still large enough to sate most picky eaters. The same cannot be said of the fare present 67 million years ago in the Cretaceous Period. Dinosaurs abound, but as reptiles they are obviously off the menu, and might even try to dine on you. Many of the early birds of the period would not be considered Kosher, nor would a good amount of the fish, as they would be "creeping" bottom-dwellers and might lack clearly defined scales. There likely would have been grasshoppers to munch on, though!
Finally, the authors travel back 310 million years, where a Jew keeping Kosher would have a difficult time finding any animal sources of food:
Although vertebrate life exists on land, the reptile-like tetrapods of this period predate any mammal or bird and would certainly “swarm” upon the land. Scales and finned bony fish are known, but none have cycloid scales. There are possible ancestors of crickets and grasshoppers, but their jumping legs were not strongly developed.
Our Kosher time traveler could simply eat vegetarian, of course. But even consuming plants gets a lot harder the farther back we go. Before humans domesticated plants, they were not as nutritive as they are now. Dating back as far as 55 million years ago, a forest might contain plenty of nuts, fruits, and seeds courtesy of angiosperms -- flowering plants. But before then, angiosperms were a relative rarity, and their seeds too small and few in number to be of much value.
Aside from serving as a useful guide for Kosher travelers to the past should time travel ever enter into reality (unlikely), the authors see their piece as a humorous, yet excellent example of science outreach.
"'Kosher paleontology' could be used for conversations about evolution that are lighter and more entertaining," they write.
"Discussing how paleontologists would address such a query illustrates how they think about the morphology, ecology, and relationships of extinct animals and thus gives an opportunity to introduce broader concepts from paleontology and evolutionary biology to a more general audience."
Source: Roy E. Plotnick, Jessica M. Theodor, and Thomas R. Holtz. "Jurassic Pork: What Could a Jewish Time Traveler Eat?" Evolution: Education and Outreach 2015, 8:17 doi:10.1186/s12052-015-0047-2