You can clone them if you have the DNA and a suitable host mother a close match to the original species. It would be exciting to see a live mammoth...
The biggest advantage to bringing animals back would be to fill niches in the ecosystem that they once inhabited. There are many ecosystems around the world where extinct animals have left holes in the ecosystem which mean that it ceases to function properly. One such instance in the eradication of the large predators in the UK.
Many of these holes could be filled by reintroducing animals from otehr parts of their range where they still exist.
Animals such as the mammoth (more possible as they tended to die in extremely cold places so often some genetic material is left in the body) could be reintroduced into Siberia to fulfill the niche that they evolved to fill
If we could clone recently extinct animals, we could reintroduce them to their natural habitats. This would repair some of the damage we've done by wiping out species like the thylacine or even the passenger pigeon.
If we cloned more ancient animals, they would have to be kept in zoos or animal parks, but they would certainly attract many tourists, making for a good business model.
The cloning of life remains a deeply controversial and vexing issue due to the ethical implications the technology creates. In reference to literally resurrecting extinct species this creates the introduction of new and alien organisms into a biosphere. Other dangers include the humane treatment as cloning cannot assure the organism may suffer through its creation or if their offspring will be viable and healthy.
the woolly mammoth became extinct a number of decades ago
No, the mammoth is extinct.
Currently, I have not heard any news on scientists cloning the Saber-toothed Tiger. As of December 2011, however, news broke that scientists plan to clone the wooly mammoth within five years. If this is a successful cloning, I will bet that scientists will pursue interest in cloning more extinct creatures.
mammoth. you had it right.
Wooly Mammoth
Yes.
The mammoth was a wild animal. They are extinct now.
Yes.
YES
Mammoths are now extinct.
nothing, it's extinct.