Revealing mistake: In the fight scene between Riddick and Johns, there is a wide shot of them both fighting over Johns' shotgun. In this shot it is apparent that it is not Vin Diesel in the shot but in fact a stunt double. (01:17:35)
Revealing mistake: Claudia Black's character "Shazza" drives the vehicle back to the ship as the eclipse starts to take place. There is a front shot of the vehicle as it is driven through the bone yard. In this shot it is obvious that it isn't Claudia Black driving the vehicle. (00:53:50)
Answer: Yes, it is her period. Considering that he lived in darkness for years, it's possible that he smells it too. It's also equally likely he realized she was a girl and that the creatures were all riled up and put two and two together. But the first explanation fits Riddick's character better.
Grumpy Scot