47 million years ago, Ida's rainforest was located on the same latitude as the southern coast of present day Spain. Floral and faunal fossils indicate that Ida lived in a warm, humid rainforest that teemed with life. Over 300 species of plants and animals have been identified - but these represent only a fraction of the life that existed here as much of the plant life would have quickly rotted in the moist jungle heat.
Many of the plants that grew in the Messel rainforest are only found in the tropics and subtropics today. They are often characterised by large leaves with pointed ends - ideal for shedding water in the humid climate. Much like modern rainforest, the interior of Ida's forest was divided into four layers. The greatest diversity of plant species lived in the canopy layer, close to the warmth of the sun. This is where Ida probably spent much of her time, rubbing shoulders with a wide variety of other climbing, leaping and flying animals.
In the dappled light of the forest floor, only a dense tangle of plants adapted to minimal light levels could survive. The gut contents of primitive horses show that laurels grew here, along with ferns, mosses and flowering plants. The mulch of the forest floor provided food and shelter to a multitude of beetles and burrowing vertebrates.
At the centre of Ida's Eocene rainforest stood the Messel lake. Its warm, sunny edges were particularly attractive to plants and animals alike. The abundance of fossilized leaves found in the Messel shale suggest that the rainforest stretched right down to the lake shore in places, despite the lake's steep, crater rim. Fossilized water lilies, grasses and conifers, indicate that the edges of the lakes were shallow, marshy and rich in aquatic life.
Unlike ordinary lakes, the Messel lake was a maar lake, created when hot magma deep beneath the ground swirled too near the Earth's surface and hit the subterranean water table. The water instantly turned to steam, and because of the pressure of earth on top, created a mighty explosion of nuclear proportions.
This created a huge crater - up to 300 meters deep - with a bank of debris all around. The crater quickly filled with rain and groundwater, creating a lake. The whole structure in cross section roughly resembled an old fashioned champagne glass: the magma at the bottom was the base of the glass; the chimney formed the stem; and the lake was the wine in the bowl. The unique circumstances in which the Messel lake was formed hold the key to the remarkable preservation of its extraordinary fossils.