Illustration of a deer tick (Ixodes scapularis) feeding on human blood. This arachnid will feed on its host for four to five days. After inserting its long mouthparts through the skin, the tick produces a cement-like compound (yellow) to keep them embedded in the skin. The tick then takes in small amounts of blood and slowly begins to expand its body size. Finally, the rapid engorgement stage sees the tick filling up with blood, sometimes expanding its body weight by 100 times. The deer tick, which is found in the eastern USA and southeastern Canada, is the vector of a number of human disease including Lyme disease.