Porcupine is the same thing, just using latinate roots rather than native English/Germanic ones.
Looking at the various translations on Wikipedia (https://de.wikipedia.org/wiki/Orang-Utans#/languages), that could be because they took the word from different languages. For example, Bahasa Indonesia has “Orang Utan”, Bahasa Banjar “Uranghutan”
https://groups.google.com/forum/message/raw?msg=alt.language...
Geology is the study of the earth.