Oldest pregnant horselike fossil found
48-million-year-old skeleton shows modern horse reproductive system developed earlier than thought

IN FOAL The oldest known skeleton of a pregnant Eurohippus messelensis mare holds an almost fully grown fetus (circled). The petite mare weighed around 5 kilograms, some 100 times less than horses of today.
Franzen et al/PLOS ONE 2015, Sven Tränkner/Senckenberg Forschungsinstitut Frankfurt (photo)