what kind of cactus? get something with bigger spines i'd say. the usual creature violently destroying plants are children. I wouldnt know what to say excpet find out whats doing it. maybe birds. your method of treatment will depend on whats pestering them.

Birds sometimes do this. Its a pain. Also squirrel-type creatures.

Any number of animals could be doing this. You didnt mention what type setting you live in or possible wildlife in your area...such as squirrels, rabbits, opossum, etc. Heck my lab shredded some of my plants. Try setting out lemon rind around your plants, many animals do not like the smell of citrus. You can also try garlic cloves, or better yet heavy garlic oil rubbed around the outside of pots and in the immediate area. If it is happening at night it probably is not birds as most birds don't fly at night - or have a good sense of smell, hence scent-repellents are not effective for birds. Finding out *what* will go along way to finding out *how*. hth - Jo