It is based on the context that the Hydrophobic Skunk is so rare that nobody ever saw him, this indicates that the regular person from anywhere cannot identify if the skunk really exist since no one has ever seen one. It is like a myth or a legend or just really rare. For the native, who has seen one or perhaps has been living with one around its area, knows the skunk exists, but depends on whether he or she knows its the name as Hydrophobic Skunk since no report was given that the skunk lives in the certain area. He or she may refer to it as just a skunk.
"Today nobody brought his or her instrument" is correct. It is common for people to use "their" in a sentence like this, but "his or her" is the more proper term.
