The beaches of Manuae's southern islet are an important nesting site for the green sea turtle (Chelonia mydas), which is listed as endangered throughout its Pacific range. Females come ashore to lay eggs at night between November and March; the absence of human habitation and disturbance makes Manuae one of the Cook Islands' most productive turtle nesting sites.
Visitors with permits who time their trip to the nesting season may witness turtles emerging from the surf after dark — an experience that requires patience, red-filtered torch lights (white light disturbs nesting females), and a willingness to wait in the dark. The Cook Islands government takes turtle protection seriously; any approach to nesting turtles must follow guidelines provided when the permit is issued.