Mulder: Are you at all familiar with the phenomena of cattle mutilations? Since 1967, over 34 states have reported unsolved cases of cattle mutilations. Trace evidence is remarkably similar. Incision marks of surgical precision. The area around the mouth and often the sexual organs have been removed. There's a substantial degree of blood loss but not a trace of blood at the scene.
Scully: How could that be?
Mulder: Exsanguination. If you were to stick a needle into the jugular of any living creature, the heart itself would act as a pump.