When we sheared our goats I ask the pro doing the shearing if he had problems with the lice all goats have. He said nope, they drop off because of body temp of sheep and goats is higher than the human body temp. He could always tell if we missed a goat during delousing (done 4 times a year). And wasn't sweet when he told us we missed one..
If you missed one goat, they would be lousy with lice..:O)
The term "crabs" usually refer to pubic lice. Once in a while we would get one in the hospital and the doctor would usually put a warning on the front of the chart, so we wouldn't catch them in the process of our care for the patient in the hospital..
I thought there was only two types of lice. And heat makes perfect sense.