Colossal Biosciences, a start-up backed by Chris Hemsworth and Paris Hilton, is aiming to revive woolly mammoths by 2028. The company, "the world's first de-extinction company", is developing a method to revive "core" genes from extinct animals and replicate those genes using the DNA of a close existing relative. The company also plans to revive the dodo and Tasmanian tiger.