By Jennifer Kvamme, DVM
Summertime is prime time for blood-sucking ticks, and your pets are walking targets for these arachnids (related to spiders and mites) to attach to and feed from. In order to prevent ticks and the potential diseases they carry, it helps to understand how these creatures develop.
There are two broad classifications for the more than 850 species of ticks. They are classed by body structure: soft ticks and hard ticks. Ticks in the Ixodidae family have a hard outer covering, called a scutum. Soft ticks – those without a scutum – belong to the Argasidae family. The most common ticks that prey on pets are the hard bodied ticks. Soft ticks are more common in the Southwest and are typically discovered in the ears of pets, where the skin in thinner.
Four Life Stages
The majority of hard ticks require three different hosts to complete their development. During this development, ticks go through four stages of life. These stages are egg, larvae (or seed tick), nymph, and adult.
Generally, adult female hard ticks breed while on the host animal and then drop to the ground to lay eggs. A female lays several thousand eggs at a time, which will eventually hatch into the larval stage, known as seed ticks. At this stage of life, these small ticks (about 1/8-inch in size) have six legs.
Ticks can’t jump, so they must find ways to attach to their hosts. They will use blades of grass and other vegetation to elevate themselves to the height where they can easily grasp onto passing animals such as small rodents or birds. Proximate biochemical signals, such as rising carbon dioxide levels emitted by a warm blooded mammal, alert the ticks to passing hosts.
This procedure is called "questing," and ticks use these behaviors to find their first host for an initial blood meal. After filling with blood over several days, the seed ticks fall to the ground again, where they molt (shed their outer skins) and become eight-legged nymphs.
The nymph will then lie in wait for a second host to attach to and engorge on blood. The nymphs prefer a larger animal as a host, such as a raccoon or possum. Following engorgement, nymphs drop to the ground where they molt yet again to finally become adult ticks. The adult ticks then go on a hunt for a third, even larger host, such as a deer or dog, where they are able to feed and then breed, resulting in reproduction (i.e., eggs).