Most gangs in Calgary are made up of young adults (although gangs have been known to use elementary-aged children if it works to the gang's advantage).
Typically, Calgary gangs do not wear uniforms or colours. They do not have a particular area of the city they call their "turf" - they operate city-wide - in every community. If you see graffiti in your neighbourhood it does not necessarily mean you have a gang problem. Generally, gangs do not "advertise" with graffiti.
The primary criminal activity gangs use to financially support themselves is selling drugs. Crack cocaine. Ecstasy. Crystal Meth. Marijuana. Other crimes may involve credit card skimming and weapons-related offences. The main reason gangs exist is to make money and maximize profits for established members. Gangs use violence to enhance their position and reputation to further their criminal enterprises.