Sentient; Brain is split up throughout the body through various nervous nodes, which prevents them from becoming a host species of the Yeerks.
|Behind the scenes|
The Hawjabrans are an alien race that the Yeerks once tried to make into Controllers. But it was impossible to do since Hawjabrans have several central nervous nodes located all over their bodies instead of a primary brain, making them usless for the Yeerks to infest. This was mentioned in The Hork-Bajir Chronicles, Yeerks attacked and captured a Hawjabran Colony Ship. After attempting to infest them, they learned that Hawjabran couldn't be infested because of numerous central nervous nodes. Despite this fact, it did not save the crew and passengers of the ship, as later an Anadalite ship found 8,000 dead Hawjabrans floating in space. In Book #8: The Alien, Ax pointed out that the Enterprise-D from Star Trek: The Next Generation looks a little bit like a Hawjabran Freighter.