Paralysis ticks have a hard body, are usually pale brown, and are about 2 to 4 mm long prior to feeding. When an adult tick feeds on your pet's blood, it increases in size dramatically, up to 14 mm long!
 

Paralysis ticks attach with their mouthparts which become deeply and firmly embedded in the skin.  The area where a tick is attached can become red, and a raised thickening or crater may appear. A crater is evidence that a tick has once been attached and feeding there.
 

While the tick sucks blood from the animal, it secretes saliva that contains toxins which are absorbed into the body, causing tick toxicity. If you find a paralysis tick or suspect your pet may have a tick, you should get them to a vet immediately.
 

Signs of tick toxicity generally develop from 72 hours after the attachment of the tick. Signs include loss of coordination, change in bark, progressive paralysis starting in the hind legs, and difficulty breathing. 

Check your pet's coat for skin for ticks daily, especially after outings. Pay special attention to: Head, neck, front limbs, skin folds, inside the ear flaps, between the toes and under the armpits.
 

If you have found a tick on your pet or suspect they may have a tick, get them to a vet as soon as possible because clinical signs can quickly develop. They may need tick treatment, such as anti-serum, which can be life-saving.