Cybermats act as the advanced guard and are mainly used for sabotage. This makes things easier for the Cybermen as the Cybermats are much smaller and can easily gain access to forbidden or secure areas.
The Cybermats first featured in The Tomb of the Cybermen. The original Cybermats had crystalline eyes and a segmented body with sensors along their base.
The 3rd generation of Cybermats were a lot larger than the previous versions, they still had a segmented body but no eyes. The Cybermat that appeared in Revenge of the Cybermen could be remote controlled.
The Cybermat that featured in Closing Time is similar in design to the 1960′s versions. This Cybermat may appear cute and harmless but beware of its bite! This is the first Cybermat to have teeth and like the Cybermen it had ‘teardrop’ eyes. The Doctor said that it had a brain, it is not known what life form the brain and teeth were extracted from.
The Cybermats featured in the 2010 Doctor Who Adventure Game Blood of the Cybermen.
Cybermites are upgraded Cybermats, they’re far more flexible and advanced. They usually travel around in groups and have the capabilities to upgrade humans.