Final answer:
The statement that ferrets are now a common tame breed is true. Domestic ferrets are different from the wild black-footed ferrets but have been domesticated and are widely kept as pets. The trend of keeping small mammals as pets is growing, with animals such as gerbils, hamsters, and guinea pigs being popular choices.
Step-by-step explanation:
The statement that ferrets, once wild animals of the great plains, are now a common tame breed is true. While the black-footed ferret (Mustela nigripes) was native to the North American great plains, they were once near extinction and have since been the focus of conservation and reintroduction efforts. Domestic ferrets (Mustela putorius furo) are indeed a different subspecies that have been domesticated and are commonly kept as pets. They are not the species that were native to the plains, but they exemplify the domestication of an animal once wild to become a common pet.
Additionally, the trade in live mammals as pets, such as gerbils, hamsters, and guinea pigs, has been a growing trend, with other unique small mammals also becoming increasingly popular as pets in regions like the United States and the European Union. Domesticated animals have been bred over generations to exhibit neoteny, which is the tendency to retain juvenile features. This process has produced a variety of animals that are commonly kept as pets today, reflecting the intimate relationship humans have with animals they keep for companionship.