From the field to the lab: there is a (smelly) story written in scats…
Anyone who has ever worked with carnivores knows that this can be a rather smelly business. Whether it involves carcasses or fresh faeces, their smell can never really be forgotten, nor can their value to study carnivore ecology!
Within the framework of our Greater Etosha Carnivore Program, we are interested in a myriad of questions, several of which can be answered with the help of scat samples. The obvious one is of course diet. Since the keratin contained in hairs is not digested, the traditional method to study diet composition has simply been to look at the prey hair remains in the faeces. For this, both dry (old) and fresh scats are appropriate. One "simply" has to sample a few (~25 hairs) from the scat, make some transversal cuts and cuticle imprints and look at them under the microscope to identify the species they belong to. Easier said than done of course! But new methods have emerged, and we can now take full advantage of the progress made in the genetics field to decipher what prey has been eaten. This method is called DNA metabarcoding, and it relies on the researcher having access to DNA sequences specific to each prey species present in the area where the scat was collected. Which ever DNA amplifies through PCR identifies the prey consumed. This method however, requires fresh scats, and here comes the smelly part of the business!
Recording sample details and location & bagging it!
But it doesn't stop here! With fresh scats, using DNA again, one can also identify the individual who had deposited it or to study diseases and parasites occurring in the area, again via genetic but also through visual observation. Another realm of possibilities is the study of the gut microbiome, which is the collection of all microbes, such as bacteria, fungi, viruses, that naturally inside the digestive tracks.
Lion faeces with numerous nematodes (tiny white dots)
But before all of these analyses can be done and conclusions be drawn, we should all have a warm thought toward the field researcher who has spent a couple of hours processing these fresh scats into small tubes and containers in a closed-up lab room… And for the person using the lab afterwards ;-)
Processed samples ready for storage
So next time you are in the bush and see a fresh and smelly carnivore scat, you can look at it in wonder instead of disgust, remembering all the stories this pile of crap has to tell…