Not once is it claimed that they are unique in this ability, infact the first line of the article: > Octopuses have alternating periods of "quiet" and "active"

Not once is it claimed that they are unique in this ability, infact the first line of the article: > Octopuses have alternating periods of "quiet" and "active" sleep that make their rest similar to that of mammals, despite being separated by more than 500 million years of evolution.