The vampire (1945)

After a look at some strange creatures, the narrator and camera take us to the Chaco forest, on the borders of Paraguay, Argentina, and Brazil, where a vampire bat lives, desmodus rotondus, attacking wildlife and domesticated creatures, killing small ones by draining all their blood and killing large ones by leaving a parasite in their bloodstream. Four inches long, with a 12-inch wingspread, we see it walk, approach a victim, pull out a patch of fur large enough for it to engage its teeth, then lap six or seven ounces of blood. Its saliva may be an anesthetic keeping its victims from waking. A stub nose and harelip contribute to its efficiency and its hideous look.