The ant is part of the hymenoptera family. It is perhaps the most commonly-found animal form on the planet. They can even be found in the polar regions. The ant species live mainly in societies. Workers are the most plentiful.
Females have a complete, mostly defensive venomous device.
In Europe, even multiple bites are rarely dangerous, but they are irritating and frankly unpleasant. Some tropical species can cause strong or even serious reactions, for example the fire ant which bites and then sprays its venom onto the wounds it makes.