Grabbers as they were dubbed in Bloodlines are sentient, independent parts of the African Graboid.
Hunting and Science
Able to hunt on their own, they can climb up rocky surfaces and strike where the Graboid cannot. This leaves them more vulnerable to being attacked. They do not seem to be homologous to the tongues of the American graboid, and might actually be an entirely different animal species of their own, sharing a symbiotic relationship with the African graboid.