The most common place to put a tag that identifies an animal is on the ear, specifically on the middle third of the ear between the upper and lower ribs (cartilage ridges). This is known as tagging the "auricle" or ear flap. For livestock like cattle, the tag is usually placed in the middle to lower part of the ear, with the tag stud (the male part) on the inside of the ear. Proper hygiene and care are important during tagging to prevent infection. For pets such as dogs, tags are typically attached to the collar rather than directly on the body. In summary:

• Livestock identification tags are most commonly placed on the ear (auricle).
• Tags should be positioned in the middle third of the ear between cartilage ribs.
• For pets, tags are usually attached to the collar.

This method balances animal comfort, tag visibility, and durability.