The Most Invasive Prehistoric Animals

1. Tyrannosaurus Rex: T.Rex was one of the largest land carnivores of all time. With a large territorial need, they would require extensive space to roam and hunt, potentially encroaching on areas of human civilization and causing catastrophic damage to their infrastructure while looking for food. They could dominate the top of the food chain, causing a destabilization of the ecosystem as they would likely outcompete modern predators. 2. Dromaeosaurs: These small-to-medium-sized, agile, and highly social carnivores would become invasive through their sheer numbers and hunting prowess. They could outcompete modern predators for food and territory due to their intelligence and pack hunting strategies. 3. Megatherium (Giant Sloth): Mega herbivores like Megatherium would be highly consumptive of vegetation. Their large size meant they would eat a lot, so their reintroduction could drastically alter forest landscapes and cause a ripple effect through the ecosystem, allowing for overgrowth of certain plants and the potential extinction of others. 4. Woolly Mammoth: These extinct mammoths shared many characteristics with today's elephants, which need large amounts of food and water daily. This they might outcompete and displace other herbivores, upsetting the balance in current ecosystems. 5. Plesiosaurs: Much like the T. Rex for the land, this marine predator could dominate aquatic ecosystems due to their size and hunting abilities, possibly outcompeting current apex predators and causing declines in fish populations. 6. Passenger Pigeon: These birds are a prime example of an invasive species. They historically gathered and traveled in enormous flocks, caused massive amounts of destruction to agricultural crops. Their reintroduction would again lead to large-scale crop losses. 7. Smilodon (Saber-toothed Tiger): Smilodons could become invasive in modern times due to their hunting prowess, specialized for taking down large prey. They could potentially outcompete modern large predators and also pose a serious threat to both human and livestock safety given their size and strength. 8. Quagga: Similarly to horses, Quaggas would potentially be invasive due to the amount of vegetation they consume. This could lead to overgrazing, causing disruption in land ecosystems and water cycles. In sum, there are many ways prehistoric animals could be invasive if brought back. Predators could outcompete current species for food and territory, while herbivores could cause habitat destruction and throw ecosystems out of balance. In any case, reintroducing any extinct species would cause ripple effects throughout ecosystems, both aquatic and terrestrial, likely leading to unforeseen problems.