Hedgehog breeding is an area where even the most experienced breeders comment that we still have an awful lot to learn. In the last year, we have been taking care to carefully track several aspects of hedgehog pregnancy, in order to better understand some of the variables that related to gestation and survivability of the babies. Our sample consisted of 75 breeding attempts, with 65 litters resulting (87% rate of conception between December of 2002 and August of 2003.

In undertaking this study, all females were weighed right before they were put with the male, then again 30 days later. From these numbers, the amount of weight change was calculated. For females who had babies, the range of weight change was from -4 grams to 204 grams. The average weight change was 80.5 grams, with a standard deviation of 51 grams. Interestingly, the amount of weight change appeared to have very little to do with the number of babies that were born (9% correlation) or the mothers weight to begin with (8% correlation). There did appear to be some association of the amount of weight gain with the survivability of the babies, that correlation was 26%. The amount of weight change was, predictably, correlated with whether or not the female was pregnant (48% correlation) and how many days after the 30 days the baby was born (-42% correlation, meaning the more she'd gained at 30 days, the fewer days until the litter was born).

In this sample, the average length of gestation, measured by days from when the female was first placed with the male to the date when the babies were born, was 38 days with a standard deviation of 4. All females were kept with the males for 30 days, and the range of gestation was 34 to 57 days. The average litter size was 3, with a standard deviation of 1, while the average number of survivors was 2, with a standard deviation of 1.5. This was a slightly smaller litter size than was found with a prior data analysis that was performed in `1998. The percentage of babies surviving to weaning age, 65%, was consistent with the prior study.

The average weight for females in this study was 401 grams, with a standard deviation of 135 grams. The range was 184 grams to 774 grams. The correlation of amount of weight gained with the mother's pre-pregnancy weight and gestation was 16%. The mother's size appeared unrelated to the number of babies born (4% correlation) or the number of babies who survived to weaning age (10% correlation). There did appear to be a positive relationship between the mother's pre-pregnancy weight and whether or not she conceived (30% correlation).

These data suggest that females who are large may be somewhat less likely than females who are smaller to conceive. They also suggest that mothers who have little weight gain are at a higher risk for destroying litters, though certainly, there are many other factors that contribute to loss of infants in the nest.

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