Tick Education: Identification
There are 13 known species of ticks in Minnesota. The majority of them are known as hard ticks because they have a hard body and a very identifiable ‘shield’ behind their head. Of the hard ticks, only 3 are commonly encountered by humans: the American dog tick, a.k.a the wood tick; the blacklegged tick, a.k.a. the deer tick; and, the brown dog tick.
Tick identification can be very difficult. While color is helpful, it can’t always be relied upon. Size is also not reliable, as ticks change size based on age, sex and how recently they’ve eaten.
The shield we mentioned earlier, right behind the head, which is more pronounced on males than females, is the most reliable tick identification method. While the shield always remains in the same spot no matter what, on females it will tilt until it sits more vertically than horizontally when she is engorged with blood after or during a feeding.
American Dog Tick/Wood Tick (Dermacentor Variabilis)
The American dog tick is dark brown with whitish or yellowish markings for a shield. They are most commonly found in the spring in open fields and the underbrush of hardwood forests, but continue to be active throughout the summer.
Tick identification tip: they feed on a variety of mammals, including: humans, dogs, cats, raccoons, chipmunks, voles and white-footed mice.
An American dog tick usually takes two years to complete their life cycle, spending one summer as larvae, another as nymphs, and only living as an adult until sometime between April or June, dieing upon laying eggs.
It’s urgent to use tick identification on the American dog tick as it’s known to carry the disease Rocky Mountain spotted fever, but it’s rarely encountered in Minnesota.
Blacklegged Tick/Deer Tick (Ixodes Scapularis)
Blacklegged ticks are reddish-brown with very dark brown head, legs and shield. They look very similar to the brown dog tick (below), except the blacklegged tick has longer mouthparts.
Tick identification tip: they feed on a variety of mammals, including: humans, dogs, horses, birds, white-tailed deer, raccoons, white-footed mice and more.
A blacklegged tick usually takes at least two years to complete their life cycle, spending one summer as larvae, that winter and spring as nymphs, turn into adults in late summer. Females die the following spring after laying eggs.
It’s urgent to use tick identification on the blacklegged tick as it’s known to carry Lyme disease. In Minnesota, southeast, east central and north central area are at the highest risk to contract the disease. Most cases of Lyme disease occur in June and July from bites from nymphal blacklegged ticks.
Blacklegged ticks also carry: human anaplasmosis, babesiosis and Powassan encephalitis. These are potentially severe illnesses that often begin with flu-like symptoms.
Brown Dog Tick (Rhipicephalus Sanguineus)
Brown dog ticks are, well, brown, with a very dark brown shield. They look very similar to the blacklegged tick (above), except the brown dog tick has shorter mouthparts. They are most active from spring through fall.
Tick identification tip: they feed mostly on dogs, and cannot survive through the winter outdoors, though they can survive inside of kennels and homes with dogs. They can feed on humans, but cannot survive on the blood of humans.
Female brown dog ticks can lay up to 3,000 eggs under baseboards, behind radiators or other places in the home. Within 3 weeks to 2 months, the larvae hatch and search for a dog. After feeding multiple times, the adults will mate and the female will die after laying a single batch of eggs.
It’s urgent to use tick identification on the brown dog tick, as it can easily be confused for the blacklegged tick, which can carry Lyme disease. The brown dog tick has been known to carry the disease Rocky Mountain spotted fever, but it’s rarely encountered in Minnesota. They may also transmit canine ehrlichiosis and babesiosis to dogs.