As a result, all quarians by necessity dress in highly sophisticated enviro-suits, to protect them from disease or infection if they are injured. The most distinguishing feature of quarian biology is their weak immune system, compounded by centuries of living in sterile environments. Male quarians, however, appear to lack a third toe. Aside from hands and legs, their general body shape and sexual dimorphism is similar to humans. Their lower legs are bowed backwards significantly, compared to asari or humans. They also have three thick fingers on both hands which include a thumb, an index finger, and a long finger, similar to the middle fingers for humans, as well as three toes on each foot. Quarian facial structure and hair actually makes them the most similar to humans in physical appearance. Their eyes can see into the ultraviolet end of the spectrum their suit HUDs can show information in those wavelengths. Their ears or ear analogues differ in a noticeable fashion from those of humans, with references made to 'what for the quarian version of an ear'. Quarians have an endoskeleton, lips, teeth, and two eyes with eyelids and tear ducts. Quarians are generally shorter and of slighter build than humans.
