The Trunk-sucker is a small, flightless, plump, noisy, quick, gliding, arboreal flyer from the Pocket Forests of Darwin IV. They feed on plaque-bark tree sap with their butterfly-like proboscises and are the usual diet of daggerwrists. They come in a number of different species.

These gliders soar from tree to tree, attaching themselves with a powerful suction organ and claws. Once attached to a trunk, the trunk-suckers are apparently impossible for the daggerwrists to remove. It is necessary for the hunters to hook them on the wing, using their honed wrists or lower jaws, a feat which challenges both species' aerobatic survival skills.

At times, though, if a Trunk-sucker is too old or weak, it cannot attach itself to the bark all that well, leaving it vulnerable to a Daggerwrist prying it off, knocking it to the forest floor and parachuting after the dying flier.

Groups will rest at what are nicknamed roost-trees.

Sometimes, Trunk-suckers will feed from gashes on the trees made by climbing Daggerwrists. Often, Daggerwrists will return to many of the same trees they have previously visited before and wait for Trunk-suckers to feed from their climbing gashes.