Tag Archives: ecology

Psssst….That’s My Torchlight!

A bright torchlight is a must-have for a bat-eared fox field biologist. With a bright torchlight one can easily identify the owner of a suspicious pair of eyes (particularly, owners with dagger sharp horns) and avoid walking into the grasping branches of thorny acacia thickets. Most importantly, a torchlight helps when following a battie during a nocturnal follow. Information collected during follows give us an idea about batties’ diet, territory usage, and social interactions with other foxes. I can keep the spotlight on my focal fox as it dashes up the side of a sand dune or through a maze of driedoring bushes. Occasionally, a fox decides to takeoff like Superman, and it is very challenging to keep up with them when I am only allowed to follow at a “non-threatening” speed-walk. Mostly, my torch helps me to feel safe – it makes the night almost familiar to me, and is a constant reminder of how visually-centered we are, as human beings. There is no way my other senses would compensate for the absence of my torch at night.

From the beam of my torchlight I have observed foxes locate insects by integrating information from multiple senses. Like all canids, the senses of smell and hearing are wonderfully developed in bat-eared foxes. A fox will pause, sniff, and turn its head and ridiculously large ears around before dashing off to gobble up termites, pick a caterpillar out of a bush, or even dig up a mouse hole. By turning their large ears about foxes hear even better in stereo (this is called binaural hearing) and can focus on their prey items. While the foxes’ ears and nose do help them locate insects, it doesn’t quite always give them the balance I expect. For example, on a particularly nippy winter night I observed one of our foxes, Bain, digging up ant nests. He picked around a bush, sniffing and swiveling his ears about before pouncing a bush and digging it up. A couple of times he dug too deeply for ants, and then fell head-first into the deep hole he had just dug. It was impossible not to laugh!

Avoiding trouble by finding batties in daylight...

Avoiding trouble by finding batties in daylight…

During a follow a fox sometimes spends just as much time patrolling its territory as it does foraging, and possibly a fox uses smell to locate familiar places in their territory. Just as I use a torch to light up the night to make things familiar to me, fox urine is quite useful when marking over other fox pee or on termite foraging patches. Ilor, in particular, travels several kilometers during a follow. He will urinate on a random interesting spot after sniffing it, then another spot, and another, and so on. Occasionally foxes are known to wee on researchers boots or research equipment as well. This is how my field torchlight came to smell. I had set down my torch to feed Ben raisins, but Ben had other ideas. He came up to the torch, sniffed it, lifted his leg, and “pssst,” my torch now stank of battie pee. I still am not sure if I should be offended or happy that Ben claimed me as his own… I of course later sanitized my torch, but I still advise not smelling it too closely.

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Threesome at Pharside (A tale of 3 foxes)

Escobar

Escobar, but no Emmental

On a cold winter night, I was walking around Pharside Dam as I wanted to just check in on Escobar (one of our habituated males) in the area. After I called for about 5 minutes, he pitched up from behind a grassy patch and waited for some raisins. Happy that he was looking so good, I left Escobar around and started my search for Emmental, the other habituated male in this part of the reserve. We hadn’t seen Emmental for a while despite searching on a regular basis, so alarm bells were starting to ring. My steps took me on a big loop in the area, without much luck.

As I was walking back on the road, I spotted eyes in the distance. I took my packet of raisins out and crinkled it, hoping this pair of eyes belonged to one of “our” foxes. It was indeed a habituated fox, but not a battie! It was Ray, the Cape fox (yes, they all come with name tags)! He came running at me for some raisins. With winter on us now, foxes are all super eager for this treat! I stayed with Ray for a while when Escobar found us again.

Ray, the Cape fox, looking hopeful and apprehensive.

Ray, the Cape fox, looking hopeful and apprehensive.

I was getting rather excited and curious about how these two species will interact. Batties are slightly bigger than Cape foxes, and from the few interactions we have witnessed, they seem to be dominant. As usual, Escobar chased Ray away immediately. Definitely, these raisins were his to eat! He had to stay on his toes though, as Ray kept hanging around, hoping for a lucky raisin, and it was only Escobar’s growling and puffed-up tail that stood between him and the juicy treat.

Escie defending his stash

Escie defending his stash

But Pharside still had surprises in store for me that night, as another batty suddenly approached. To my delight it turned out to be Emmental! He was looking extremely healthy and robust compared to Escobar, so I was certain Escobar would now have to give up his stash. Escobar thought so too. He crouched down, growling, tail raised and puffed up, in a very submissive position. But within a fraction of a second, the tables were turned. Escobar jumped up and started a fierce fight with Emmental, eventually winning and chasing the bigger fox away. And for the next 30min, I was in the company of these three foxes.
When Emmental finally started to drift away, I simply could not follow him, as both Ray and Escobar were on my heels! It was a very peculiar stand off, with both of them circling me whenever I paused for a second, and Ray trying to keep his distance form Escobar. I was impressed by Ray’s tenacity.

Walking back to the car, I started wondering. How is dominance established between batties? Is the hierarchy stable or variable through time? What are the benefits of being dominant and the costs of being subordinate? Is it access to the best foraging spots? Or to more mating opportunities? These animals tend to forage together so socially – is there even a proper hierarchy? Is there any way that a Cape fox could beat up a battie? And I realized I had my work cut out for me: I need to habituate plenty more foxes during a very cold, long winter…

Up-close and personality

It is my first field night in the Kalahari, and I feel like I am wearing every piece of clothing I brought with me. My body is nice and warm except for my fingers and toes. They are permanently encased in iceblocks. As hard as I try, ensconcing them in wool gloves and socks, they never seem to get warm. Most people don’t realize how low the temperature gets in the desert, but it is bone-chillingly cold.

The crunch of a raisin bag sounds across the sand, low shrubs, and thorns hanging at just the right height to leave a mark on your face. Suddenly, three furry faces appear and start prancing over to us. Three bat-eared fox (batty) pups have come to get their treat of sweet raisins. I am dumbfounded at how close they get to us. One little boy comes and pulls on my shoelaces. These animals are habituated!

I’ve studied a number of species as a biologist, from humongous (300 kg) sea lions to thumb-sized (6g) pocket mice, but this is my first experience working with an animal that you can walk right up to and follow without them running away. To walk with the bat-eared foxes as they meander through the tall, thorned bushes, gobbling up termites and caterpillars is a truly wonderful experience as a biologist and naturalist. Most science projects that study individuals aren’t able to do something like this; they trap individuals every so often, take the necessary measurements and samples, and then release the animal into its natural setting. If you want to study their social behavior, you do so at a distance (so you don’t upset any natural behavior) at the cost of interaction details.

My PhD on yellow-bellied marmots epitomized this approach. We trapped individuals every other week, took their weight and different morphological measurements, painted a unique symbol on them and let them go. I watched, from a great distance, as they played, fought, and ran from predators. My work focused on consistent differences in individual behavior — or personality — so it was imperative that I knew the animal I was watching and with whom they were interacting. This could be difficult at such a great distance and often the small details about their personality could be lost.

The batty project allows me to study these social little animals so close that I can examine how one individual differs from another without worrying about losing much detail. I can tell who is biting whom, who’s growling, who’s whining… This approach does call for an ongoing process of habituation, though, as new (wild) individuals keep on coming into the population. So, next up is to habituate as many foxes as possible. This is a slow, tedious process, but totally worth it.

A double edged sword — Ruan

Similar to other PhD students in behavioural ecology, I spend months in the field and have to sort out the various and inevitable problems that come with remote fieldwork. Our supervisors trust us to do a good job of keeping the project going and getting all the necessary data. They cannot really keep a heavy hand on us – email correspondence is about the only way of managing contact. Except when you hear the words, casually dropped, “I am coming to the field.” This almost always strikes fear into the heart of a student. What are they going to think about the progress I made? Will they agree with the way I sorted out some of the problems? Would they have done things in a similar way? Will they be happy?

 

A hard-working PhD student in action

A hard-working PhD student in action. Photo credit: Elizabeth Wiley

Approaching my seventh month in the field, I was anticipating the excitement of the breeding season that was expected to be in full swing by the time I arrived. Judging by the number of insects flying into my face and up my shirt, I did not think we were experiencing a drought. However, my worst fears came true…there was no evidence of breeding, and no pups! This is definitely not a good sign for someone whose PhD is based on paternal care. The extreme conditions and apparent food shortage (?!) have had a detrimental effect on the foxes’ attempts at successfully producing pups this year. Whatever the reasons might be, I needed some guidance, and the remoteness of our study site has made contact with the outside world challenging to say the least. I was actually relieved to hear my supervisor was planning on dropping by. Maybe she could steer things in a better direction.

We had endless discussions on potential solutions to my dilemma… As part of such a new project, I was a little restricted in terms of finding new angles within the range of data we have collected so far. We finally settled on the “simplest” solution — I would include home ranges and marking behaviour, mediated by hormones, in my thesis. Of course, this easy answer now meant I have to follow foxes for the entire night in order to get a better idea of the distances these little guys travel. I started to prepare for endless long nights in the field.

And then it happened… one of our vixens, Bertha, took me to a secret den, where I found our first three (and so far, only) pups of the season. The excitement was tangible, even if I was abashed at being ‘out-foxed’ by the apparently virginal Bertha for a while. Of course, my supervisor left just after this wonderful event, and the problems are lining themselves up yet again. We’re doing full-night focals to collect that extra data. But very, very soon, we will be able to follow the first ‘project’ pups in our nightly observations. And we remain at the combined mercy of fickle Mother Nature and technology, constantly messing with our most carefully made plans.

 

Finally -- bat-eared fox pups enter the picture!

Finally — bat-eared fox pups enter the picture! Photo credit: Ruan de Bruin

The rabbit incident.

Nights with the batties can become quite social, as they’re constantly interacting with other animals. Sure, mostly the interaction involves eating or being eaten. I adore seeing them mow through termites, their tail raising as I know they are about to chase a sun spider, scorpion or mouse, or go to their favourite spot for peanut beetles to drop. More often than not, they’re the ones running away. Their arch nemesis —our local Nguni cattle — go out of their way just to chase the batties around. It’s a rather social affair, especially during the longer nights with our foxes.

Earlier this week, then, I was hoping to see another entertaining rodent chase when I spotted a sizable rabbit right next to our skittish little Bertha. But the moment I saw Bertha’s tail go up – hunter style – I knew I was in for a treat. The chase was over in a second as she almost instantly pinned the rabbit down, going for the neck. It reminded me of how a leopard would suffocate its prey. But of course, in this event the predator and prey were almost the same size. And Bertha was suddenly far less adorable. She carried the rabbit back and once the rabbit stopped moving she started nibbling all over its body, almost as if she didn’t known where to start… Eventually, after playing with her food a little while, she managed to get past the fur. After having a couple of mouthfuls, good old Bruce came along. Bertha then left with a piece, leaving Bruce with the prize, as he began wolfing down the rest,

Bertha, shortly after proving herself an outstanding hunter.

Bertha, shortly after proving herself an outstanding hunter.

leaving almost nothing for scavengers. He even ate the fluffy tail, which he gobbled up whole. Now I know this is horrid, but I could not stop imagining the next day’s fecal samples, all wrapped in fluffiness. Despite its goriness, this was actually a very exciting night – nobody that I know of has ever seen rabbit on the bat-eared foxes’ menus. It’s usually invertebrates and maybe a mouse or two. Is this some new choice by this particular fox, or is this actually common and other researchers have just missed this because it happens so fast? We’re keeping a close eye on Bertha in particular, hoping that time will sort this question out.

Battles and Broken Borders — Samantha

Towards the end of winter, field work became a bit too predictable: I find my fox, we wander around, and end up more or less where we started. But the onset of the breeding season is causing more than romance to blossom, with batties popping up where they’ve never been seen, and unrest manifesting in previously calm neighbourhoods. The docile creatures that they are, I expected most of these changes to be genteel. In one case, however, a foraging altercation took an interesting turn.

One of the areas I visit is home to an odd pair of foxes, Aristotle (Ari for short) and Scruffy. Scruffy is a particularly ill-kempt vixen. While I have no doubt that at least some of Scruffy’s problems are rooted in her thriving community of on-board parasites, I’ve slowly come to realise that part of her problem is Ari. There is just no way to sugarcoat this: Ari is an abusive husband. I’ve seen him chase Scruffy, nip her, snarl at her and just generally mistreat her for no apparent reason. He’s not the loving husband that batties are supposed to be. And it turns out that Ari just acts like a mean drunk in any context. One evening, Ari turned up unexpectedly while I was following Bruce. At first, Bruce sauntered off, pretty much ignoring this snarling new arrival. A couple of minutes later, Ari tried to muscle in on some ants Bruce was gulping down and suddenly all hell broke loose. Now I’ve seen battie “aggression” before: foxes approach each other, growl a bit, or make half-hearted attempts to give chase. But this night, the boys meant business. Bruce and Ari launched into one another, the perfect snarling, biting cartoonish dust-ball. I couldn’t tell one battie apart from the other. And then, in a few seconds, it was over. Ari was sent packing down the road, presumably back to take his frustrations out on his long-suffering wife. Bruce meanwhile shook himself off, and conscientiously urinated on anything in his neighbourhood that didn’t run away.

This is the first serious fight I’ve seen in two months and it will certainly be interesting when we find out what hormonal changes are driving this behaviour. I can’t help wondering if the vagabond syndrome and serious aggression will become commonplace. Love (and War) are in the air.

Battie by starlight — Samantha

My introduction to bat-eared foxes was a strange one. On our way to the reserve, Keafon, my wise field guide, asked if I minded stopping to count dead foxes en route from Upington. I thought it a rather morbid hobby but she explained that part of her PhD research focused on these road casualties, and the necessity of this research quickly became clear. Kill after kill we came across was a battie, by far the most common animal run over on the road. Our count ended on no less than 37 of them, and I found myself thinking that it was better for me to see these dead batties before growing fond of any live ones.

Finally, as we neared the reserve, I caught my first glimpse of a live fox, dashing across the road ahead. Later that evening, in the reserve proper, I saw a second individual all over-sized ears and quizzically pointed snout checking us out. I was getting more excited by the minute to see these animals in action, and the next day I got my chance. Keafon introduced me to a lovely lady fox, Garbuncle, who promptly curled into a ball, yawning lazily at the setting sun. Well, I found myself thinking, this is going to be easy! I mean, they don’t really do anything, do they?

Less than half an hour later I was fast-walking through the bush after a fox hell-bent on chasing down flying beetles.

“It gets a bit hectic around this time,” Keafon panted besides me. I was soon to learn that this beetle hunt was a nightly occurrence, with every single fox living up to its moniker of “battie” as the beetles come out. The second evening, Keafon suggested we follow Bruce, a very well habituated male who’d been following us around the night before. “Hah, easy!” I thought again, wrapped in the warm glow of optimism. I mean, Bruce barely leaves you alone, right?

Wrong. Shortly after we started, Bruce was haring across the countryside enthusiastically, and I was once more in awkward pursuit. Thankfully, he stopped regularly to show me interesting things like: “This is where you can find juicy ants” and “See this here? Dig it up and you’ll get termites.” He seemed to be taking an interest in my well-being because clearly I was too stupid to survive on my own in the bush. Finally, after an exhausting hour and a half, Bruce decided I’d been put through my paces enough. Parking his butt on a sand dune, he proceeded to lick his balls with every evidence of satisfaction, throwing me an intermittent loving glance under the Kalahari stars.

I felt certain we’d be sharing a string of evenings under the stars and I doubt any of them are going to be dull.