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).