Lucanus cervus, the European stag beetle, may be confused with the following species:
European rhinoceros beetle (Oryctes nasicornis)
The rhinoceros beetle is completely red brown (not always visible in the dark) and does not have yellow rings or spots on the legs. Males only have one big pointy projection on their head, just like a rhino. Females only have a really small projection. Rhinoceros beetles have broad, compact legs while stage beetles have more small and longer legs. Also, the antennae of both species are different. The European stag beetle has comb-shaped antennae, the rhinoceros beetle fan-shaped (often folded up as a club).
Lesser stag beetle (Dorcus parallelipipedus)
The lesser stag beetle looks like the female European stag beetle but is usually smaller and is completely dull black with fine yellow lines in between the segments. This beetle is more flat while the European stag beetle is more round.