Important lessons from entomology

Lice are specialists. Fleas are generalists.

You cannot get lice from another species of animal. That whole “don’t touch a bird nest because you’ll get bird lice” thing is totally untrue; bird lice would die very quickly on a human body. However you CAN get fleas from other animals; if your dog or cat has fleas you can quite easily get fleas from them.

…and having kept several of them in a box for two or three days, so that for all that time they had nothing to feed on, I found, upon letting one creep on my hand, that it immediately fell to sucking, and did neither seem to thrust its nose very deep into the skin, nor to open any kind of mouth, but I could plainly perceive a small current of blood, which came directly from its snouth, and past into its belly… [emphasis added]

The lengths to which Robert Hooke went in his studies is admirable and, frankly, disgusting. This is his analysis of a louse.