Page:The Golden Hamster Manual.djvu/53

 the back and frequently a beautiful golden shade by weaning. Growth is remarkably gradual from the 12th to 16th week.

Lift him, abdomen upward, and note the rounded sex organ forward from the anus approximately $1/4$ inch at weaning, $1/2$ inch at 6 weeks, and $3/4$ inch in adulthood. In Illus. 53, Male group (A) shows distance from penis to anus at various ages.

Lift her, abdomen upward, and note her sex organ, very near the anus, has slit-like opening running lengthwise with the body as in Female (B) group, Illus. 53.

Skilled handlers may distinguish sex at birth. If helpful, use magnifying glass for first early study of sex distinctions.

Now, check Female (C) group in Illus. 53. Mammae (nipple) lines are in faint outline by 5th day; discernible dots by the 7th; conspicuous by the 9th. This observation is most dependable for use in removing litter culls as well as in controlling sex ratio to be weaned, and may be used fairly early in litter life when caretaker becomes experienced.

Pedigree on commercial breeding stock is unnecessary. But, within one's own hamstery, such pedigree data prevents the mating of immediate relatives without knowing it, but guides line-breeding when desired. That is the main value of knowing the pedigree of hamsters. Illus. 54 shows such a pedigree. The sire's grand parents were owned locally. The dam’s parents were purchased from a commercial hamstery. In this



series of records, males are known by letters and females by numbers. Female 22 was from Dam 16, by Sire D. Breeding Record, as per Illus. 55, shows her production. Served by Sire K; littered 2-26-44; litter culled