Crazy ants (Anoplolepis gracilipes), also known as yellow crazy ants, are an introduced exotic species native to south west Africa. They are widely regarded as environmental pests and are included as one of the ‘world’s 100 worst’ invasive species.
The name ‘crazy ant’ is derived from their erratic walking style and frantic movements, especially when disturbed.
Adult crazy ants are yellowish tan, about 5mm in length, with long antennae and a long slender body. Any ants that are black, dark brown or dark red are unlikely to be crazy ants.
While crazy ants have no functional sting, they spray formic acid as a defence mechanism, especially when disturbed.
In large amounts, this acid may burn or otherwise irritate skin and eyes of animals and potentially humans.
For further information, see the Department of Agriculture Fisheries and Forestry