"due in part to their well-developed olfactory bulb and a large surface of olfactory mucosa, about 5.8 square centimetres (29⁄32 square inch) in area, which is about twice that of humans"
on the wikipedia article on cats, and stopped with an incorrect assumption.
The article on "cat senses" states:
"A domestic cat's sense of smell is 9-16 times as strong as humans'"
More fool me.
<stubborn> That said, he is a behemoth, not a cat, so who knows what his sense of smell is like.</stubborn> :)
To be fair, since he didn't even try to use his sense of smell, one should deduce it's not so great (because otherwise he would have used it). But it's kind of easy to instead think he foolished failed to do it or that the author didn't even think about it. It's probably a case of a story not doing what the reader would have expected/hoped to see.
it's obvious that the old man got them probably with the help of the adventurer leader that they met last chapter but i do wonder how. those 2 weren't exactly weak and they were in their element on their own home turf yet they seem to have been captured and captured without leaving a trace.
well we can guess that guy will be dying soon now he was suspicious from the moment he was introduced and we know from the previous chapter he was going to kidnap the fairies.