Hyena coprolites

Digested bones or those bearing bite marks are common features in the caves, as are coprolites, fossilised animal faeces.

Today we bring you a coprolite of a spotted hyena (Crocuta crocuta) found at Vanguard Cave. These coprolites contain much more information than one may think, since many of them conserve a large amount of pollen. The analysis of these pollen help us to reconstruct the plant palaeo-landscape of Gibraltar. We will briefly explain the process.

The landscape is made up of different plant species, many of which are consumed by herbivores such as red deer, ibex or horses, which while feeding on these ingest a large quantity of pollen, which accumulate in their digestive tract. If one of these herbivores is hunted, or after its death, is scavenged upon, the pollen in their bodies are transferred to the digestive tract of the carnivore, in this case a hyena.

Hyenas used these caves as dens, taking animal carcasses there for consumption or even consuming animal remains left behind by Neanderthals. After defecating inside the cave, the faeces could have then acted as a sticky trap collecting even more pollen grains from the environment. Eventually the hyaena droppings would have been covered by sediments over time, forming part of the caves’ fossil record.

After excavating and identifying them, archaeologists extract these coprolites from the caves so they can be the subject of study by palaeopalynologists. After processing in a laboratory, the ancient pollen grains can be extracted from the coprolites for identification and counting. We can use these data to create diagrams which allow us to visualise the species and their abundance at a particular time in our past, or to record the evolution of the landscape over time if we have samples from different stratigraphic levels.