Ixodes scapularis, commonly known as the black-legged tick, is a species of tick found in North America and known as the carrier of Lyme disease. This tick can also be referred to as the deer tick or the bear tick. The scientific name Ixodes scapularis is derived from its unique scapular shield, which covers the top of its body. The black-legged tick also has several other synonyms, including Ixodes pacificus, which is a species of tick found mainly on the West Coast of the United States. Other common names for this tick include the castor bean tick, the sheep tick, and the hunter's tick. Despite the different names, they all refer to the same species of tick and share similar characteristics.