Can a Dementor produce a Patronus?

Why is Snape the only Death Eater who can produce a Patronus? [Duplicate]

JKR stated in a web chat that Death Eaters couldn't produce cartridges because they didn't need them.

Samantha: Was Snape the only Death Eater who could produce a full Patronus?

JK Rowling: Yes, because a Patronus is used against things that the Death Eaters generally create or fight with. You wouldn't need a Patronus.

Essentially, they're allied with the Dementors so they don't seem to need a way to defend themselves against the effects they have on them. It is possible (although this is only speculation) that even if they tried to learn, the experiences that made them want to become Death Eaters could mean that they did not have a sufficiently happy memory to let the spell work . Snape's extraordinary love for Lily is the exception; it seems like it's probably the only (very) bright spot in an otherwise miserable life.

Still, I'm not sure if they would ever have been taught. Cartridges may not be part of the Hogwarts curriculum, even at the NEWT level. Harry learned how to conjure up a Patronus in his third year, and he taught a number of other students during sessions with Dumbledore's army in his fifth year, but there is never a point where they actually learn the spell during a regular lesson.

They cover the theory of it and what it is used for, but there are never practical sessions on how to cast the spell. It is also repeatedly mentioned how difficult it is to produce a physical Patronus, how impressive it is that Harry can summon one, and how many (most?) Skilled witches and wizards are unable to do so. Seems counterproductive in trying to teach a spell that a large percentage of students may never be able to perform adequately.

Red_Shadow

JKR's words only make sense in the accurate narration of the books because of the alliance between the Death Eaters and the Dementors. The problem is, all of the Death Eaters went to Hogwarts long before this alliance (end of OotP). In addition, some Death Eaters have been imprisoned by Dementors. It seems like a Patronus spell with enough power would have been a great way to take a mass break in prison. Besides, no army leader would ally himself with a group of beings he could not fight if turned against him. Voldemort wasn't a fool.