A question about wet tail

[melanieandlizzie]

I noticed my hamster had something on his bum so I took a picture because I wondered if it was wet tail?

(you can click on the picture to see it bigger)

[souffle]

I think he just has increased pigment around his vents now melanie. This is perfectly normal in males as they mature. They normally get darker ears and also the scent glands get darker and sometimes a bit raised up.
Unless he has diahorhea or something swollen or a lump I would not worry about the darker skin on these areas.