Exhibits a highly pronounced polymorphism among its worker caste in Camponotus mus, which is structurally divided into minor, media, and major workers or soldiers. The body length of these workers varies greatly from 6 to 13 millimeters, whereas the founding queens are noticeably larger, frequently exceeding 15 millimeters in total length. Its body color is predominantly a matte black or deep charcoal, featuring a highly diagnostic, dense coat of golden-yellowish hairs on the gaster that gives the abdomen a velvety, shimmering appearance when exposed to light. The head is large and heavily sclerotized, particularly in the major caste, housing powerful mandibles designed for excavating soft, decaying wood, although they lack a stinger and instead utilize an acidopore to spray formic acid as an active defense.

Geographical distribution: Is natively distributed throughout the southern regions of South America. Its presence is widely recorded across Argentina, particularly in the central and northern provinces such as Buenos Aires, Santa Fe, Córdoba, and Entre Ríos. The distribution range of this species extends continuously eastward and northward, encompassing the entirety of Uruguay, the central and southern territories of Paraguay, and the southernmost states of Brazil, including Rio Grande do Sul and Santa Catarina, where humid subtropical and temperate conditions favor its survival.

Habitat: Inhabits a diverse array of natural, rural, and highly urbanized environments, showcasing a remarkable degree of ecological plasticity. In pristine ecosystems, it preferentially constructs colonies within dead wood, fallen trunks, decomposing stumps, and beneath the bark of living trees in temperate grasslands and xerophytic forests. However, it has adapted exceptionally well to urban and suburban areas, where it regularly nests inside human-made wooden structures such as roof beams, door frames, wall cavities, and window sills, sometimes becoming a structural nuisance.

Feeding: Is a highly opportunistic, omnivorous feeder that derives most of its carbohydrates from sugary substances. It actively collects floral and extrafloral nectar, but its main energy source is the honeydew produced by aphids and scale insects, with which it maintains a mutualistic relationship. To fulfill its protein requirements, crucial for larval growth, it feeds on decomposing organic matter, dead or live insects, and various small arthropods. Food distribution within the nest relies heavily on trophallaxis, ensuring that liquid nutrients are shared efficiently among all colony members.

Behavior: Exhibits primarily crepuscular and nocturnal activity, though workers can frequently be observed foraging individually during daylight hours on warm days. This social insect relies on a sophisticated chemical communication system based on pheromones to establish and maintain foraging trails from the nest to food sources. When disturbed, workers drum their gasters against the wooden substrate, producing audible vibrations that warn the rest of the colony. They are highly territorial and will aggressively defend their territory using their jaws and chemical sprays against competing colonies.

Reproduction: Progresses through holometabolous development, comprising egg, larva, pupa, and adult stages. The primary reproductive event is characterized by nuptial flights that occur during the warm spring and summer months, typically on hot, humid afternoons or evenings following heavy rainfall. During these events, winged males and virgin queens swarm in large numbers to mate in flight. After mating, the males die almost immediately, while the newly fertilized queens shed their wings and search for a suitable crevice to establish a new claustral colony, raising their first brood of workers solely using energy stored in their regressed wing muscles.

Conservation status: Has not been evaluated by the International Union for Conservation of Nature Red List. Given its high adaptability, abundance, and success in human-modified environments across its native range, the species is considered highly resilient and secure, facing no immediate conservation threats.