The study of arachnids is fascinating. Tarantulas are especially fascinating, due to their humongous size and wide range of dispositions. Theraphosa blondi, for example, is gargantuan in size, with a nasty temperament. Others are unbelievably gentle, such as the classic Grammastola rosea.
Someday soon, I'd like to say something about Grammastola aureostriatum, which is one of my favorite species of all time.
Trivia: What do you call the fore and aft body segments of a spider? They are commonly referred to as the cephalothorax (head+thorax) and the abdomen, respectively; however, that's not strictly accurate. The thorax is supposed to house various organs which are actually present in the aft body segment of a spider. The more scientifically accurate terms are prosoma and opisthosoma.