The past, the poop and palynology

Do you ever imagine how your neighbourhood looked before humans rocked up?
How about back when giant ground sloths pottered in your garden, or a Tyrannosaurus bedded down where your house now stands?

It’s only a blink ago, in geological time.

Of course we tend to forget that hopping and squeaking, right outside our doors, are the direct descendents of those monstrous beasts.

Photo posted on Flickr by kibuyu.



 OK, I know sparrows are a bit of a comedown, but if you're ever up close and personal with an ostrich’s foot, you’ll never again doubt the dinosaurishness of birds.



Living outside my own backdoor (well actually it’s about 0.5 km away) is a seriously anachronistic beast. Small and inconspicuous with a curmudgeonly air, it cunningly hides its connections to an illustrious past.

  

You see if you pop back 40 million years here, you won’t meet many of Africa’s iconic beasts. There’ll be no antelopes or zebras, buffalos or giraffes; even the hogs hadn’t tromped in yet. (Of course, there were mongooses; but who could imagine a world without them?).

Back in those days, Africa’s principal veggie-eaters came from an entirely different family; creatures whose great grand-pappy also sired the mastodons and mammoths. These herbivores stomped and frolicked in a carnival of diversity, ranging from diminutive mouse-like critters to rhino-sized brutes; some slick and fleet of foot, others dumpy and lumbering.

So who were these creatures?

Hyraxes.

Yep, that’s right, good ol’ dassies.

Ellies' rellies? Rock hyraxes (Procavia capensis) might look marmot-like but they've more in common with their elephant kin. Both are scrotum-free (their testes are internal), lack a gall bladder, sport impressive tusks, have hoof-like toenails and endure pregnancies that last forever (7-8 months in hyraxes).
Photo posted on Flickr by Koets.

Small human shown for scale.
Photo (taken on the Cape Peninsula) by Danie van der Merwe.

Sadly, the arrival of ruminants put paid to the Golden Age of Hyraxes. Out-competed by these consummate vegans (who would have thought that chewing your food twice could prove so beneficial), hyraxes withdrew to the nooks and crannies of the continent. Today only four species remain.

Possibly because of this fall from grace, rock hyraxes are obstreperous little beasts. Although they live in colonies of up to 35 animals (one macho male with a harem of sisters, daughters and aunts), social relations are strained. Look closely at a mob of hyraxes basking atop a rocky outcrop and you’ll notice that they never sit facing one another; they fan out like iron-filings around a magnet.
When they bounce down off the rocks to graze as a herd (harvesting a different section of their range each day) they also arrange themselves like this. And when a hyrax wants to join a huddle or enter a crevice, it reverses in backwards.

Weapons of dassie destruction.
Fights (mostly between males) can be fatal
due to the hyrax's tusks.
Photo by Brian Burger.

Why?

Well in hyrax-speak, eye-to-eye contact is equivalent to a rude hand gesture and, let me tell you, a pissed-off hyrax is scary. It growls, it gnashes its molars, it erects the black fur around its dorsal gland (a smelly, goo-secreting patch in the middle of its back), it curls its lip and slashes with its gruesome tusks.

Oh yes, despite their heart-warming shape, hyraxes are not heart-warming beasts. Unlike my charming mongooses, they will not suckle one another's pups; heck, they won't even groom each other!

And in the breeding season everything gets much worse due to a massive influx of testosterone: the dominant male's testes increase 20-fold in size! 

   

For the biblical ‘coney’, soaking up the sun isn’t just a leisure activity. Being of ancient origin, the hyrax’s thermostat is faulty so it basks and huddles to stay warm (even ‘stacking’ on chilly nights) and hides in shady crevices when it's hot.
Photo by Steve Krane.



Quite a mouthful. With their top incisors transformed into tusks and their lower ones converted into a grooming comb, rock hyraxes must nip off their veggies with their molars. Their huge gape lets them take bites as large as a sheep’s (as my deformed thumb will testify).

Photo by Damien du Toit.

 



Baby hyraxes are born in summer (all the girls in a colony give birth syncronously). They immediately clamber up on to Mum's dorsal gland: their favourite hang-out spot for the next five months.
 Photo by Paul Genge





A teat of one's one. Infant hyraxes divy up Mum's nipples, remaining faithful to their chosen teat/s for the entire 3-5 month suckling period.



Thanks to the tenacity of this weird little animal (it's only got three hind toes: i.e. proof of weirdness) we can begin to imagine the bygone fauna of Africa. But it’s actually one of the rock hyraxes more mundane habits that’s proven most helpful to our understanding of the past.


Like all sensible creatures, rock hyraxes deposit their poop in latrines. Their toilet facilities are conveniently located close to the colony’s sleeping quarters (usually beneath a rock overhang) and are used, unswervingly, for centuries. The hyraxes not only poop here, they merrily splash pee over the rocks, and when the calcium carbonate in the urine crystallises, it not only creates tell-tale white stains, it cements the droppings in place. Protected from the weather, these piles of poop provide an amazing, stratified compilation of the past.


A pile of poop or an
invaluable historical record?



Now I didn’t realise this until I researched this post, but hyrax middens are the bee’s knees for palynologists (pollen enthusiasts). You see air-borne pollen grains stick enthusiastically to fresh hyrax poop, so by sifting through the layers of stratified shit and identifying the attendant pollen, these diligent souls can ascertain past climates. Thanks to radio-carbon dating we know that a hyrax midden from the Karoo provided 1130 years of compiled hyrax history, and a Namibian midden yielded 2000 years worth of ongoing shit data! But it doesn’t stop there. In dry climates, hyrax dung readily fossilises, and fossil middens have shed light on 20,000 years of southern Africa’s past.

Go hyraxes!

 

 

Reparation. "This picnic is mine!"
Photo by Tim Parkinson.

 

Smelly little messages

 

A gratuitous mongoose piccy.




PLOP!

Something slipped from my thermos flask and splashed into my mug of tea.

I didn't see it happen. I was sitting on a boulder, with one eye on my mongooses, pouring a quick cuppa while they searched for bugs.
But I heard the plop.

What the...?
Oh god!
Bobbing in my tea was a sticky, black mongoose poop nestled in a small plastic bag.

How did this happen?
Well, when I'm out in the field I carry two thermos flasks. One contains my morning brew and the other is filled with ice to keep faecal samples fresh and perky. Unfortunately, the two flasks look very much alike. And sometimes I'm just not paying attention as I stuff a sample into a flask...

As I carefully fished out the neatly labelled bag, I could see that the tea had seeped inside. Presumably, worse things had seeped out. I didn't know which aggrieved me more, the loss of my tea or the sample. You see, after five years working with dwarf mongooses I've come to share many of their perceptions of the world (scary, I know). And for a dwarf mongoose, every poop is sacred.

Unlike other family members, dwarf mongooses don't just broadcast their droppings far and wide. In fact, regardless of the leg-crossing involved, they'll only poop at the group's special scent-marking sites or at latrines located by each of their sleeping mounds. Now you may think the early morning rush to use the bathroom is hectic at your house, but it's nothing to the jostling that goes on when a mongoose group gets out of bed. Tumbling out of hole, they scramble and dash across to the latrine, a dozen little furry bodies jockeying for position all at one time. Even mongooses that don't need to go make a huge effort to squeeze something out. And once the group has headed off to forage, it's not unusual for someone to realise they haven't completed their toilette and, all in a panic, they'll go racing back. But why do they go to all this trouble?

Does scat mean scat? Latrines were once seen as Keep Out signs but, in many species, they're really community notice boards, all aflutter with phone-number fringed personal ads.
Image borrowed from here.

We know from experiments with banded mongooses and meerkats that mongooses can discriminate between the poop of different individuals. And not just their nearest and dearest; they can also tell the droppings of neighbours from those of strangers. And banded mongooses act very edgy indeed if they encounter a neighbour's poop steaming on the wrong border.

But how do they do it? Well like all carnivores (including Fido and Puss) mongooses are blessed with anal glands that secrete a fatty substance. This goo sits about cosily inside an anal pouch where it's feasted on by hungry bacteria. The bugs leave behind an array of volatile carboxylic acids (which stink), and which ones you end up with (and how much of each sort) depends on which types of bacteria are lurking in your anal pouch. Since every individual has its own unique bacterial assortment, everyone's acid profile is unique, and thus so is their pong. (I do have to wonder how antibiotics affects all this, for example in zoo animals.)



Comet leaving a message.


And of course excrement is also chockfull of all the hormones coursing through the depositor's veins. So for those with a sensitive nose, the gen is endless. Is he stressed? Is he feeling mean? Is she willing?

With so much personal information being bandied about, it's not surprising that individuals sometimes indulge in a bit of self promotion.
At meerkat latrines, the ladies post alluring come-hither messages for the guys next door while their male group-mates dash about madly, trying to mask these billets-doux with stinky macho threats. The end result is an absurdly male-biased latrine whose shitty composition bears no resemblance to the actual group make up.



The take away message proffered by a meerkat latrine.
Image borrowed from here.


In contrast to meerkats, banded mongooses are far more narcissistic. They consider poop an in-house affair. Everyone is too interested in getting the low down – or putting one over - their sexual rivals (who come from inside the group, not out) to spare much of a sniff for the leavings of the opposite sex.


But what are the dwarf mongooses up to? Why do they – unlike other mongooses – religiously pile up huge middens outside their sleeping dens? It's not as if dens (i.e. termite mounds) are in short supply; there are 200 to 300 in each group's territory (I know because I've plotted every one) and the group sleeps - and latrines - at only about 30.

It's in an attempt to figure out why my mongooses don't waste their waste that I daily risk the integrity of my morning cuppa. The smelly little samples I spoon up are destined for use in taste sniff tests. The idea is to present a smorgasbord of poo to selected individuals and see exactly what takes their fancy. Are they more intrigued by the droppings of outsiders or group members; rivals or lovers?


 

A mobile perfume counter. On the right are a male and female poop from the sniffer's own group; on the left they're from a strange group. Don't panic! The one in the middle isn't from a mongoose on steroids; it's an antelope turd, just to be sure they aren't simply attracted to anything that pongs.


My first attempt at this experiment was not a success.
In fact, it was one of those ghastly moments when you see your research career evaporating before your eyes.
No one sniffed anything.
They totally ignored every single dropping.

In desperation, I grabbed up a poop and stuffed it right under Pleiades' nose. She screwed her eyes shut and turned her head away with such overt revulsion I was shocked. I couldn't have evoked a more negative reaction if I'd done this to a human! I could almost see her thinking, 'Who would leave that here!'

That was when it hit me.

Dwarf mongooses never leave their droppings lying about in the field, yet here I was presenting samples to animals as they trotted about foraging. It was like tossing post-it notes under the feet of busy shoppers and wondering why no one read them.

I tried again at one of the group's scent-marking sites.
And low and behold, they scratched and sniffed!
O frabjous day!
Of course this makes the whole procedure much more tedious because the samples must be kept frozen until just before they're presented. So I spend my days trailing after the mongooses, trying to anticipate when they're going to stop in at one of their toilet facilities. When I believe a lavatory stop is imminent, I have to madly thaw the samples down the front of my shirt (and, yes, it does feel as ghastly as it sounds).

I'm still undertaking these trials so I can't yet tell you what messages are encrypted in my mongooses' latrines. However, it looks as if the ladies (who are very status conscious) are most interested in getting the low down on one another, while the guys can't resist a lovely female poop, particularly if it's from someone they haven't met.



Bugbears enjoying themselves at the information exchange (i.e. scent-marking site).



How to find a mongoose

Regardless of how much you love your job, there's always some aspect of the work that's tiresome, frustrating or just plain disheartening.

For me, it's finding the mongooses.

Take today: while everyone else was happily munching hot-cross buns or overindulging on chocolate, I was out there struggling through thorn-thickets, hour after hour, totally failing to find my mongooses.

I've got nothing against radio-collaring study animals, but dwarf mongooses are – well – dwarf. The small collars they need have a limited battery life, so the mongooses need to be recaptured every few months. As a biologist working with wild animals, I believe that if it's possible to obtain your data non-invasively, you should, even if it means you're sometimes inconvenienced.

Just at the moment, I repeat this mantra to myself frequently. You see dwarf mongoose groups have territories of 30-40 hectares, and while it's fairly straight forward to find them eight months of the year, in the summer wet season, when the bush transforms into a lush, tangled jungle, the 'inconvenience' sets in.

So how do you find a 3-inch-high mongoose in 40 hectares of bush?

You get up early!

The mongooses sleep in the ventilation shafts of disused termite mounds, and each group has about 30 of these sleeping mounds in its territory. In the cooler winter months, the mongooses sleep late and lounge around their refuge for hours, soaking up the sun, romping in play and grooming one another. To find them, I simply have to check each of their refuges first thing in the morning.

Latrine left by Bugbears at their overnight refuge.

Even if the group has already set out foraging, I still know where to start searching because they considerately leave behind a latrine at their sleeping place. They are also very keen on scent-marking, so whenever the group passes a scent-marking site (and they have about 40 of these scattered through their territory), they'll smear pongy anal secretions on the logs and rocks, and leave a dropping or two. By checking these 'message posts' (all plotted on my GPS), I can track where the group has gone.

Keni contributing to Bugbear's latrine.

But in summer, everything goes pear-shaped. Firstly, the mongooses get up very EARLY. The moment the sun edges over the horizon, they come tumbling out of their mound, climbing over one another in a flurry to latrine, and hurrying off to forage. With daily temperatures reaching the high 30s or low 40s (Celsius), they can't afford to linger - by 9am they'll have to forgo foraging to lie about in the shade. So although I get up at 4 am, I'm usually not able to find them at their refuge. And the difficulties don't stop there. In summer the dung beetles are active. These poxy, little varmints come buzzing in the moment a mongoose defecates. They tussle over the droppings, gathering them up and rolling them away into the undergrowth. Within 10 minutes there is no trace of the latrine.

So I'm left tramping back and forth through the mongooses' overgrown territory, disconsolately sniffing at rocks and feeling thoroughly inadequate!

A dung beetle doing its dastardly deed.