Question: What is the name of the little horses in program 1?
Answer: The early horses shown in the series are called Propalaeotherium. This means 'before Palaeotherium', which was another early form of horse. Palaeotherium itself means 'old beast'. The particular species is Propalaeotherium parvulum.
Question: Where are fossils of Propalaeotherium (early horses) found?
Answer: The Propalaeotherium shown in program one are reconstructed from fossils found in Germany. Two species are found in the Messel shales, and other early horses are found in North America and throughout Europe. The remarkable fossils have preserved an exact body outline, allowing us to reconstruct them very accurately. One of the fossils even showed a pregnant mare with a foal inside.
Question: How big were the early horses in program one?
Answer: The early horses shown in the series are based on the smaller of two species found in the Messel shales of Germany, Propalaeotherium parvulum, which was 30-35cm at the shoulder. The larger species was 55-60cm at the shoulder.
Question: How do we know that the Propalaeotherium (early horses) ate grapes?
Answer: Amazingly, some of the fossil Propalaeotherium are so well preserved that we can see their stomach contents and so we know exactly what they ate. In fact when some of the leaves found in their stomachs were put under a microscope and shown to a botanist they couldn't tell that the leaves were 50 million years old as they were so well preserved! These are mostly leaves picked up from the forest floor. One specimen, though, had been gorging itself on fallen grapes - the same kind as we make wine from (Vitis species). Obviously a vine had been fruiting and dropping grapes onto the forest floor just before this animal died.
Question: How do we know that the Propalaeotherium (early horses) would get drunk?
Answer: Other animals tend to be affected by the same drugs as us. Even insects are affected by alcohol (think of slow-moving dozy wasps on fermenting fruit in autumn), and mammals are certainly affected in very much the same way as us.
Question: How do we know what colour the Propalaeotherium were?
Answer: Just about the only information we were missing to recreate Propalaeotherium for the program was its natural colours. Some of the fossil beetles from the same place are coloured, but this is because their colour is caused by the very fine structure of their shells diffracting the light. This structure can be preserved by such exquisite fossilisation (although their colours may change slightly). However, most mammals use pigment molecules in their skin and hair to create their colours, and these molecules degrade as the body decays. So, to design a colour scheme for the animals we looked at that of small forest deer, which live in a similar habitat. They need to avoid predators, and in the dappled forest light, dark brown with paler spots seemed to be the most common colours for camouflage.
Question: Why were the Propalaeotherium (early horses) so small?
Answer: All the early mammals around this time (50 million years ago) were small - the largest being about the size of a pig. This is because the World was covered in thick tropical forest - there simply wasn't room to get big! Being small and nimble, the little horses could browse the fallen fruit and leaves, and make quick dodges into the undergrowth to hide from predators such as Gastornis.
Question: Why did the Propalaeotherium (early horses) have several hooflets and not hooves like modern horses?
Answer: The early horses were quite similar to their relatives the tapirs (which have changed little in the last 50 million years), and had feet with several nail-like hooflets. These gave them a good grip for fast acceleration into undergrowth on the forest floor. Modern horses have only one toe on the ground, whose nail has expanded into a hoof to bear the weight. These single toes are designed for speed over a long distance on the plains.