They also don't have the pasture they would expect. Nor the gut biome to digest it. A living organism is also an entire context. Just look at the trouble we ha

They also don't have the pasture they would expect. Nor the gut biome to digest it. A living organism is also an entire context. Just look at the trouble we have getting wild animals to thrive in a zoo, where we can control the environment. The idea that an extinct megafauna could be released into whatever environment and survive, is unlikely.