They say advances in genetic engineering have brought them much closer to bringing back an animal called a Tasmanian tiger.
The tiger became extinct in 1936 when it was killed off by people who blamed it for killing sheep.
The scientists have managed to take DNA from the baby, and have now been able to recreate the animal's entire DNA structure.
It's like something out of Jurassic Park.
Lots of work to do
It would be the first time such a thing has happened.
However, the scientists could be in for a long wait, because no one has worked out yet how to create a new animal from the DNA.