Aardvarks predominantly prey on ants and termites, digging them out of the ground or from epigeal termitaries. Geographical variation of ants and termites faunas leads to variations in the species of prey consumed. Ant genera so far identified as food items include Aenictus, Alaopone, Anoplolepis, Camponotus, Crematogaster, Dorylus, Messor, Monomorium, Pheidole, Solenopsis, Tetramorium, and Typhlophone; termite genera include Allodontermes, Basidentitermes, Cubitermes, Hodotermes, Macrotermes, Microhodotermes, Odontotermes, Pseudacanthotermes, and Trinervitermes.
As well as ants and termites, Aardvarks are also known to eat the pupae of dung beetles (Scarabaeidae). Adult scarab beetles lay their eggs in dung and store them up to 40 cm below the surface, from where Aardvarks dig them up. Evidence for this comes from stomach contents, direct observation of diggings for the larvae, spoor, and dung in eastern and southern Africa.
The ant Anoplolepis custodiens, which is an abundant species, comprises about 70% of the total number of prey eaten. The termite Trinervitermes trinervoides, with its many epigeal termitaries, makes up about 20% of the diet. There are 13 other prey species known from this site, but they constitute a small proportion (about 10%) of the diet.
Seasonal changes in diet have been recorded, but reports are conflicting. In Uganda, Aardvarks are reported to eat fewer termites in the dry season than in the wet because the termites become quiescent and are harder to obtain. In the Karoo, the termite T. trinervoides becomes quiescent in winter (May–Aug), but they confine themselves in termitaries where they are highly concentrated and more easily extracted. Aardvarks regularly target termitaries at these times and consume large quantities of termites. They do not feed on termitaries between Oct and Mar.
Aardvarks move slowly when foraging, keeping their nose close to the ground, and can be heard sniffing continuously. When a nest is located, they push their snouts flat against the ground while continuing to sniff. They then either start digging frantically to reach. the prey or move on foraging. All this time the ears are held erect, indicating that hearing is probably only used for predator detection.
Aardvarks feed in discreet bouts of short duration, moving from one ant or termite nest to the next. Most feeding bouts vary between 10 sec and 2 min, but feeds from termitaries may last over 30 min. On average, Aardvarks make about 25 separate feeds per hour and may feed from over 200 nests in one night. Foraging speeds vary between 0.5 and 1.0 km/h. There are almost always some ants or termites left active on the surface at the end of a feed because the Aardvark’s tongue is not adapted to lapping them off the surface.
Aardvarks feed from subterranean nests that vary in depth from shallow scratches at the surface to depths of over 1 m Excavations of about 200 mm is the norm. Very deep excavations are normally restricted to deep-living termite species such as Hodotermes mossambicus and such feeds may last over 30 min. In the case of Trinervitermes termitaries, Aardvarks dig into the centre of the mound and below ground level where large numbers of workers and larvae are concentrated.
Some ants, such as Dorylus helvolus, do bite hard enough to cause discomfort, but the attempts of most species are ineffective. The chemical defenses of termites such as Trinervitermes spp., which deter many potential predators, do not stop Aardvarks either.
While active, Aardvarks spend the majority of their time searching for food. The small size of their prey requires them to consume hundreds of thousands of ants and termites per night, and this necessitates them spending all their time foraging to satisfy their energy requirements. Nightly foraging distances are governed by ant densities. In the Karoo, it is not unusual for them to travel 4 km or more per night, although Melton (1976) recorded distances of up to 14 km per night in Uganda (though these latter estimates were based on spoor and may not be reliable).