This might look like an ordinary rock formation, but the black material is actually preserved faeces and urine from a small mammal called a rock hyrax (Procavia capensis).
Hyraxes, which are common in Africa and the Middle East, look like groundhogs but are more closely related to manatees and elephants. They live in crevasses and pick one spot to use as a latrine. The use of the same spot over tens of thousands of years creates a layered refuse heap known as a midden that scientists can mine for palaeoclimatic data. I specialize in examining the pollen in these dungheaps for information about the vegetation and climate of the past.
Our team found this site in May, in the Cape Fold Belt mountains of South Africa, using a drone to help investigate crevasses. We were excited when we saw the extent of this midden; we think it covers at least 20,000 years. We came back after the winter to take a sample. This photograph was taken in September. My colleague and project leader Brian Chase, who has rock-climbing skills, used a circular saw to extract a wedge that we brought back to the lab for analysis.
The team will first look at radioactive carbon to determine the age of the midden layers. Then, we will analyse the stable carbon isotopes to learn what plants the hyraxes were eating, which in turn provides clues to the climate of that time. When I examine the samples, I look for pollen grains, which enter the midden both in the hyrax’s urine and faeces and by being blown in by the wind. I’ll also look for charcoal, to tell how many wildfires occurred in the region over time, and fungal spores, which can reveal which animals were nearby.
We now have a much more nuanced and detailed view of climate changes in southern Africa. The fieldwork is very demanding, requiring long days of hiking, but I love it.
Source: Ecology - nature.com
