Hmm good point. For some reason I just assumed they'd grow it in a tube.

edit: you're right, this is from the article:

To produce the calves, Colossal scientists will first identify the genes encoding the woolly mammoth's most emblematic physical traits, such as shaggy hair, curved tusks, fat deposits and a dome-shaped cranium. They will then insert these genes into the genome of closely related, and therefore genetically similar, Asian elephants (Elephas maximus).

So they're basically gonna create a new type of mammoth (basically) by gene editing an existing species..