The bulldog ant, Myrmecia, also known as bull ants, inch ants, sergeant ants, or jumper ants, is a genus of ants. Bulldog ants can grow to over 40 mm in length, with the smallest of the species being 15 mm in length. Almost all of the approximated 90 species are endemic to Australia, with the exception of Myrmecia apicalis from New Caledonia.

These ants are well known in Australia for their aggressive behaviour and powerful stings. The venom of these ants has the potential to induce anaphylactic shock in allergic sting victims. As with most severe allergic reactions, if left untreated the reaction may be lethal. These large, alert ants have characteristic large eyes and long, slender mandibles. They have superior vision, able to track and even follow intruders from a distance of 1 metre. Myrmecia is one of several ant genera which possess gamergates, female worker ants which are able to mate and reproduce, thus sustaining the colony after the loss of the queen. A colony of Myrmecia pyriformis without queen was collected in 1998 and kept in captivity, during which time the gamergates produced viable workers for three years.