Darkling beetles are a very heterogeneous family with regard to colors, shape and biology. They often look like insects of other families, including ground beetles, carrion beetles, etc. Some measure only some millimetres and others more than 3 centimetres. They are very often black, dark brown, brown or reddish, sometimes spotted or striated. .
Their habitat is also very varied. Many species like heat and live in buildings. They are common in houses, stores, cellars, bakeries, but also in cattle sheds, meadows, fields, under the bark of old forest trees, in mushrooms growing upon trees, and sometimes in mammal and bird's nests. The adults are active at night or the evening. These beetles are phytophagous or omnivorous. Some of them are among the most damaging stored product beetles (e.g. confused flour beetle, yellow mealworm beetle).