As with many "very short" English words the concept of "ape" is typically just fingerspelled.
If you are telling a story (particularly to children) you very well may choose to thump on your chest a couple of times as if you were an ape.
The sign for "gorilla" tends to just use the chest thumping movement.
If you need to distinguish between an "ape" and a "gorilla" you have a couple of options:
1. Fingerspell A-P-E and sign "gorilla" by thumping your chest.
2. Thump your chest a couple times with "A" hands (palm-side facing toward your chest) to mean "ape." Thump your chest a couple of times with "S" hands to mean "gorilla."
GORILLA or APE:
Note: On first usage, if it is important to be specific about whether your are signing "ape" or "gorilla" it is a good practice to "fingerspell" either concept at least once for clarification.
Also see: MONKEY
Also see: GORILLA
Notes: