They attach to an animal by sticking their harpooned-shaped mouthparts into the animal's skin. If a tick is scraped off, sometimes the tick's mouthparts break off and remain in the skin, causing irritation or infection. Ticks' only food is the blood they suck from their hosts, usually warm-blooded animals like dogs. Some ticks can increase their size 20-50 fold as they feed. Female ticks, and sometimes males, emit a chemical called pheromone to attract the opposite sex.
Females die after laying all their eggs.
Male live to mate several females. Ticks have a unique system for finding animals to attack. They have sense organs on their front legs that detect carbon monoxide given off by warm-blooded animals. There are about 800 kinds of ticks in the world. About 100 of these carry diseases of wildlife, livestock or people.