Zoologist professor Phil Seddon says that the defensible rationale for bringing back an extinct species is to restore lost ecological function. However, he worries about projects that don't take into account all the variables. An example of this is the "Colossal" project which is looking to revive the wooly mammoth. It's being led by geneticist George Church and there are currently no ecologists involved in the project.
Art by Eldar Zakirov