Discovery of a 48-Million-Year-Old Pregnant Horse

Researchers have discovered a 48-million-year-old pregnant mare fossil in Germany that has remarkably well-preserved remains. The fetus of this horse and parts of the mare's uterine tissues have remained intact over time. According to the Los Angeles Times, this is the oldest and only the second uterus ever found in animal fossils. The ancestors of modern horses, known as Eurohippus messelensis, were much smaller than today's horses, being only slightly larger than modern foxes. However, the shape of this newly discovered uterus is almost identical to that of modern horses. Jens Franzen and his colleagues at the Senckenberg Research Institute in Frankfurt, Germany, stated in a paper published in the journal PLOS ONE that this discovery is significant because 98% of mammal fossils discovered so far consist mainly of skull bones and a few other bones, making this find quite rare. According to Discovery, this small fetus, measuring approximately 13 centimeters in length, possesses almost all bones except for the damaged skull. Researchers believe that the mare died shortly before giving birth, although they do not consider childbirth to be the cause of death and suggest that a lack of oxygen may have led to the horse's demise. One theory regarding the mare's death is that the lake near which this fossil was discovered may have contained carbon due to nearby volcanic activity, and drinking this water could have caused the mare's death.