Alpacas are the only mammals known to directly inseminate the uterus

Alpacas are the only mammals known to science in which males deposit sperm directly into the uterus. This unusual reproductive method inflicts small internal injuries that may help improve the chances of pregnancy.

Patricia Brennan at Mount Holyoke College in Massachusetts and her team examined and dissected the reproductive systems of 10 female alpacas that were euthanised within 24 hours of mating. They found bloody abrasions throughout the whole reproductive tract, suggesting that the male alpaca’s penis had thrust its way…