Ticks can remain on a person or animal for a few hours, a few days or a few weeks if they are not removed, according to TickAlert. During this time, ticks feed by sucking blood from the host through an efficient feeding tube held in place by a cement-like secretion.
The Centers for Disease Control explains that a tick does not attach itself to the host immediately. It can take up to two hours for a tick to find an ideal feeding spot and start feeding. When it does, the host usually doesn't feel anything thanks to an anesthetic found in the tick's saliva. Additionally, ticks feed in hidden spots, which is why they can go unnoticed for a long period of time.