Summary: alien species share information with one another – pinpointing the location of enemies and each other, and also receiving alerts directly from the bacterium.

It is clear that the Kharaa are linked to one another. When a hive is attacked, nearby aliens rush to the defense. When one alien engages marines, others often choose to assist. And yet, the Kharaa do not act as one – they are fiercely individual. This, and other evidence, has lead Frontiersmen scientists to speculate that instead of a "hive mind", the aliens have "hive sight".

There is documentary evidence that the aliens seem to be responding to visual cues instead of some kind of telepathy. For instance, when an enemy is on the other side of a wall, they swivel their heads as if they can see them. When a hive is attacked, they look around wildly until they find the direction of the threatened area, then run in that direction. Speculation is that the aliens have a kind of interface with the bacterium, that uses their senses to convey information. Probably through audible cues, and their own organic version of a HUD (Heads Up Display).

If all hives are destroyed, hive sight will slowly fade away over a period of around twenty hours - not quickly enough to impact battles with Frontiersmen, which are usually resolved much faster than that.