Many animals that are extinct may have traces of deadly disease in there petrified bone marrow. Because we are cloning animals, the process of finding the origin of a disease will be reduced significantly. Whenever somebody clones a animal there is a big chance that the latest species will carry the same disease if the DNA they have made it from has tested positive they could test the animal and observe symptoms that take place du ring the sickness. When we test on animals it could kill them but if made a clone we could do multiple tests with clones and we wouldn't have to kill the animal population n. Dorsey, a clone for a horse, was apparently the vaccine for many diseases in the future.
Bringing back animals would mend for our ancestors ways. In the past over hundreds of thousands even millions of species. Whoever has a bear pellet in there garage or a place which they own is a main cause of extinction. Because of all the DNA we have a dodo bird which went extinct hundreds of years ago if we were to clone them we could be the first generation to perform de-extinction. Running out of time to mate, tigers are beginning to die,