[[Monster: gorilla-silverback|robinloft]] The Monster Manual is constrained by page count. There are a limited number of animals (beasts) in Appendix A: Miscellaneous Creatures. There are some obvious compromises and some are pretty glaring. On the plus side, all three species of North American bears are represented: Black Bears, Brown Bears, and Polar Bears. This makes sense because bears are formidable opponents in a fight.

On the other hand, the higher primates are represented only by a broadly defined Ape, which is a clade of animals that represents 20 million years of evolution and dividing into gibbons (the so-called lesser apes), plus orangutans, gorillas, chimpanzees, and humans. I wanted a little more nuance in my campaign world, so we have forked the Ape entry from the SRD into a Gorilla entry and a Chimpanzee entry.

Want to know an absurd level of detail about the design process? We’ve got you covered. Here’s the video:

https://www.youtube.com/watch?v=-ugFP61250U

Enjoy!