Gedd

Gedds are a species of aliens in the Animorphs book series. They evolved on the same planet as the Yeerks. The Gedds are a primate-like species, with terrible vision and bad motor skills. They served as the first hosts for the parasitic Yeerks.

Gedds are described as being like 3-foot tall yellow-eyed monkeys. For no coherent biological reason, the Gedds evolved with one leg significantly shorter than the other, restricting them to an inefficient limp. Compared to humans, they are slow, weak, and nearly blind, but they are capable of accepting a Yeerk, they are numerous enough to be infested (relatively) easily, and offer a young Yeerk the magic of vision.

Gedds and Yeerks evolved together naturally, and at some point, Gedds became the species Yeerks first learned to control as hosts. When the first Andalites arrived on the planet they were aware of the Yeerks' use of Gedds, but Prince Seerow, leader of the mission, felt this symbiotic relationship was understandable considering the Yeerks' weak natural forms. It should be noted the books are not quite clear at the exact intelligence level of the Gedds, i.e., whether or not they can be considered sentient, although describes a Gedd as having feeling both fear and bewilderment, as well as having a name.

Gedd-Controllers were used in the founding days of the Empire, when, armed with knives, clubs, and a single Andalite handheld Shredder they slaughtered two dozen Andalite warriors and seized the Andalite ships stationed on the Yeerk homeworld to fly into the night. In these early days, any Yeerk considered important enough to have a Gedd host was considered very fortunate, but by the time the main events of the series took place, Gedd-Controllers were very low-level, as better hosts, such as Hork-Bajir and humans, were available.