Varren are predators native to the planet Tuchanka in Mass Effect.
Varren are quadrupeds that have features resembling Terrestrial reptiles and felines. Typical specimens appear to be about 50-100 kg and come in a variety of colors. Like all life originating from Tuchanka, varren are highly adaptable, allowing them to thrive in many environments. They survive by hunting or scavenging any other living things in the vicinity.
Varren became common around the galaxy in the aftermath of the Rachni Wars, transported by krogan to combat zones and to new colonies. They have been accidentally transported to other worlds as well, making them pests in many parts of the galaxy.