Ulape is the girly sister of Karana. She's the one who notices the Aleut girl in the first group of hunters who visit the island. At the beginning of the book, she's Karana's best friend. She represents sisterhood and companionship. Though she appears only in the beginning of the novel, she is a big part of Karana's memories keeping her tied to the past.
As Karana tells us, Ulape is "vainer" than Karana and loves to wear earrings. Ulape is also in love with the man Nanko. When Ulape boards the ship to leave the island, she paints a blue stripe across her nose to show that she's still unmarried (and an eligible bachelorette). Here she represents marriage and the traditional role of women on the island. Later, when Karana leaves the island for good, she also paints a blue stripe across her nose, suggesting the power of these female traditions.