Orangutans are primarily frugivores (fruit-eaters) and 57–80% of their feeding time is spent foraging for fruits. Even during times of scarcity, fruit can still take up 16% of feeding. Orangutans prefer fruits with soft pulp, arils or seed-walls surrounding their seeds, as well as trees with large crops. Figs fit both preferences and are thus highly favoured, but they also consume drupes and berries. Orangutans are thought to be the sole fruit disperser for some plant species including the vine species "Strychnos ignatii" which contains the toxic alkaloid strychnine.