Sexing Your Hedgehog
Females have two genital openings that are very close together with no space between the two. These openings are located right in front of the tail. You can also see the nipples that are easily apparent in some females, though a lack of obvious nipples is NOT an accurate sexing tool.
The genital openings of males are spread apart, with the rectum right in front of the tail and the sheath opening appearing as a "belly button" in the center of the abdomen. Testicles are internal in hedgehogs, and do not hang outside of the abdomen, but are sometimes visible as a pair of grape sized lumps between the sheath and the rectum. Male hedgehogs also have an internal penis, that extends from the sheath when they are excited. This is a long slim often mottled in color appendage that can be quite startling to people who aren't aware of what they are seeing.
In most cases, it is possible to sex hedgehogs even from a very young age. In very small babies, the gaps between openings in the males are much smaller, and are sometimes difficult to determine, but by the age of 2 weeks are almost always clearly defined.