I am sure we all see both of these phrases used commonly, but is there a reason as to why the terms 'natural predator' and 'natural prey' are used as opposed to just 'predator' and 'prey'?
Below are two examples of each amongst numerous others from Wikipedia.
The Wikipedia article on Wolverine says
Wolves are thought to be the wolverine's most important natural predator, with the arrival of wolves to a wolverine's territory presumably leading the latter to abandon the area.
The Wikipedia article on Leopard seal says
The only natural predator of leopard seals is the killer whale.
The Wikipedia article on Leopard says
The leopard is primarily threatened by habitat fragmentation and conversion of forest to agriculturally used land, which lead to a declining natural prey base, human–wildlife conflict with livestock herders and high leopard mortality rates.
The Wikipedia article on Reptile says
Snake farming has been troubling for conservation in the past as it can lead to overexploitation of wild snakes and their natural prey to supply the farms.
Are there preys that wouldn't be natural preys to their predatory animal? Are there predators that wouldn't be natural predators to their prey?