Here’s that great story about Rock Hyrax urine as climate proxy you’ve always wanted to read.
From the University of Leicester news: Ancient urinary deposits provide a unique insight into Africa’s prehistoric climate change.
image: Wikipedia
The Rock Hyrax is a remarkable animal. Native to dry, rocky environments throughout Africa, you would be forgiven for assuming that it is a large rodent, with its short legs, short neck, rounded ears and overall resemblance to a particularly large guinea pig or a coypu minus a tail.
And yet, in defiance of expectations, the creature’s nearest living relatives are elephants and manatees. This in itself should be enough to make any research involving Rock Hyraxes worth reading.
But these furry fellows have a distinctive behaviour which, by good fortune, enables climatologists to study the environmental history of rocky areas where traditional techniques – such as taking a core – are not viable. Rock Hyraxes, it seems, are very particular about where they urinate and defecate. They like specific locations underneath rocky overhangs and generation after generation of Hyraxes will use that same spot – called a midden – over and over again. For literally thousands of years.
Some of these middens can date back 30,000 years or more. That’s the Stone Age. That’s actually the Upper Palaeolithic period!
The urine crystallises and what you end up with is a block of solid, stratified material which provides the sort of historical record that is otherwise impossible to find in these dry, rocky parts of the world. Within the midden is a record of Hyrax metabolytes as well as particles which have passed undigested through their systems (and the occasional bit of organic material that just happened to get blown there). These can be accurately dated, giving an indication of how the vegetation – and hence the climate – has changed over the millenia. And that’s what some researchers in our Department of Geography are looking into.
Just to be completely unambiguous about this:
Geographers at the University of Leicester are studying the prehistoric climate of southern Africa by examining lumps of thousand-year-old crystallised wee from something that looks like a rat but is actually more closely related to the dugong.
How brilliant is that?
Dr Andrew Carr and Dr Arnoud Boom from Leicester are part of an international team led by Dr Brian Chase from the Institut des Sciences de l’Evolution de Montpellier. Funding for the research has been provided by the Leverhulme Trust and the European Research Council and papers on the topic have so far been published in Quaternary Research, in Geology and in the snappily named journal Palaeogeography Palaeoclimatology Palaeoecology.
Hyrax middens were first used by a South African palynologist named Louis Scott who naturally concentrated on their pollen content. The current team are the first scientists to study this extraordinary resource on a molecular level, examining animal metabolytes and plant biomarkers. Equipment at Leicester is being used to measure the bulk nitrogen and carbon isotope contents, and to identify individual plant and animal biomarkers. Colleagues in Belfast are able to accurately peg the age of a given sample using radiocarbon-dating techniques.
Hyraxes are common creatures; indeed in some areas they are considered pests. Their middens are however pretty smelly, and these ancient urinary deposits can be tricky to reach. Fortunately, Dr Chase is an experienced rock climber – that’s him in the picture equipped with angle-grinder and gas mask (cutting this stuff kicks up a lot of dust that you really don’t want to breathe in). Initially samples were knocked off with a hammer and chisel but once it was realised that cut and polished middens were finely laminated, more care was taken to extract neat samples using a micro-drill.
Paleaoenvironmental knowledge of southern Africa, which encompasses countries such as Botswana and Namibia, has always been very fragmentary and largely reliant on ocean core records. The data from the Hyrax middens open up a whole new realm of research into how some of these dynamic environments have changed over 30,000 years or so. The next step is to compare this data with established models of climate change.
Rock Hyraxes have always been interesting to anyone with a fascination for zoology, not least because of their elephantine link which is a staple of ‘interesting animal facts’-type books. But their excretory habits, or rather the potential use of what they excrete, is now raising them to a whole new level of interest.
- University press release
- The potential of plant biomarker evidence derived from rock hyrax middens as an indicator of palaeoenvironmental change. doi:10.1016/j.palaeo.2009.11.029
They also do this for Pac Rat middens in America. they use it to look at DNA too: http://www.springerlink.com/content/hn074h3028440258/
They’ve used it to study the interactions of Native Americans in what is now New Mexico with their environment: http://www.springerlink.com/content/hn074h3028440258/
I can’t believe there hasn’t been the following comment so far: This story is a pisser!
Environmental interest in animal wastes is not new. Twenty-five years ago, I received a batch of monster helicopter service bills for a hydroelectric project we were developing in Washington State. When I queried the development manager, he gleefully reported we were being forced under the terms of our environmental study to collect “goat scat” (turds) from the mountains surrounding our proposed site. When I asked what goat eating habits had to do with my modest little project he was at a loss to explain. Apparently, some federal agency operative simply thought it would be interesting to find out what the goats were eating at my expense.
In an unrelated aside, I was also forced to hire a guy who had been certified by the U.S. Forrest Service as being able to make the exact sound of a female spotted owl in heat. Each night, he sat on my proposed plant site and did his “hoot”. If any horny male owls had responded, it would not have been “Mr. Hoot” who got screwed; it would have been me. Such is the lot of those who attempt to construct any power plant in the U.S., renewable or not.
Claude Harvey
” The Rock Hyrax is a remarkable animal. Native to dry, rocky environments throughout Africa…”
” Some of these middens can date back 30,000 years or more. That’s the Stone Age. That’s actually the Upper Palaeolithic period! ”
A rock denizen that inhabits the same place for generations up to 30,000 years means not much has changed in that dry, rocky environment in 30,000 years. That is a statement all of its own. Just map out the dens and how long they have been around.
No study needed.
I can’t find a reference at this time but there is a small packrat with specially shaped teeth that will strip off the salt-enhanced outer layer of leaves to get at the inner (less salty parts). This fits with a couple of earlier comments regarding the long time frame of the adaptation of the plants and animals. The climate could not have changed very much over these tens of thousands of years. For those interested in such topics here is a site followed by a quote within a quote:
http://www.desertusa.com/mag05/aug/food7.html
The desert vegetation’s conquest has been tracked largely through the “analysis of plant and animal remains preserved in fossil packrat…middens [or nests],” according to the U. S. Geological Survey’s Land Use History of North America. (See Chapter 9, written by Craig D. Allen, Julio L. Betancourt and Thomas W. Swetnam.) “packrats gather nearby plant materials and accumulate them in dry caves and crevices; there, the plant and other debris [including animal remains] are cemented into large masses of crystallized urine (referred to as amberat), which can persevere for tens of thousands of years The extensive archive of sorted, identified, and dated [by the radiocarbon method] material represents the richest and best-documented source of plant remains in the world ”
John F. Hultquist says:
“The climate could not have changed very much over these tens of thousands of years. ”
Actually the climate in the southwest has changed quite drastically over that time interval, and animals and plats have had to move long distances to track the changes. Remember that 15,000 years ago most of Utah was one huge lake (Lake Bonneville) and most of the intermontane valley in Nevada were lakes too. There was even large lakes in Death Valley and Panamint Valley.
I know this isn’t the forum for this but:
‘……….And yet, in defiance of expectations, the creature’s nearest living relatives are elephants and manatees. This in itself should be enough to make any research involving Rock Hyraxes worth reading….’
i Find the funny part to be the Hyrax evolutionary tree. The twists and turns biologists will have to make to explain the evolution of it should be interesting. I’m not a big fan of evolution. The stressing, epigenetic forces, and number of genetic changes required to drive the precursor of the Hyrax to morph into an elephant, a Hyrax and a Manatee, given the stability of Gene Regulatory Networks, firmly established even in the precursor of the Hyrax/elephant/Manatee, to be undermined by the stability of the behaviour of the Hyrax. Piles of Chopra aimed with strained consistent resolve over 30,000 years doesn’t sound like the environment to explain the driven changes resulting in the Elephant/Manatee offshoots. The environment sounds stable.
And yet, in defiance of expectations, the creature’s nearest living relatives are elephants and manatees. This in itself should be enough to make any research involving Rock Hyraxes worth reading.
Wouldn’t the samples be compromised by Dung Beetles and the like?