Interesting canon.
taken from
http://halo.wikia.com/wiki/HuragokWhile the Prophets guide, direct, and manage Forerunner research and technology, it is the Engineers caste who must excavate, unlock, and transport Forerunner artifacts, though the Prophets insist that any admission of that fact is heresy. These remarkably helpful and docile aliens are patient, almost completely silent, and exceedingly reserved in their work and its religious implications.
Engineers are the scientific and engineering backbone of the Covenant and its economy. They float via bladders that let off a gas that is lighter than air, and their many tentacles are able to split into many fine cilia, with which they are able to manipulate machinery. Engineers are capable of quickly learning the functionality of new technology. On one occasion, an Engineer was observed by the Master Chief dismantling a vehicle's engine, assembling it into various other working configurations, and then returning it to its original state, all in a matter of seconds.[4]
Huragok "reproduce" by gathering the needed (or available) materials from their surroundings to build another Huragok. Up to three Huragok take part in this process, relaying all the information that they have learned to their "offspring." Given sufficient raw materials, a pair of Huragok can produce a unified replica of themselves in approximately 45 minutes; the addition of a third Huragok cuts the time down to 30 minutes. Understandably, it is advantageous to have as many Huragok contribute to this process as possible, raising the "intelligence" of the offspring.