Why would a woolly mammoth cloning project require elephant egg cells?

In the context of cloning and somatic cell nuclear transfer (SCNT), elephant egg cells are required because they provide the necessary biological environment to facilitate the development of a cloned embryo.

In the SCNT process, the nucleus of a somatic cell—such as one collected from a frozen woolly mammoth—is transferred into an enucleated egg (an egg cell with its own nucleus removed). The cytoplasm of the egg contains specific factors that reprogram the donor nucleus, allowing it to function as a zygote and develop into a blastocyst.1

Because the Asian elephant is the woolly mammoth's closest living relative, its eggs are the most suitable candidates to serve as the host for this genetic material, providing the compatible cellular machinery required to initiate and support the development of the embryo.12