Category Archives: field biology

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.

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…

Batties and boxes — Sam

Returning to the Kalahari to work on batties becomes a more daunting prospect when the research project is your own. There are considerations such as whether or not your experiments are feasible in the field and – importantly! – whether the foxes are going to co-operate. My idea was perhaps a tad complex… I designed a series of memory trials that required the foxes to investigate an experimental arena with a bunch of little boxes in which they had to dig no less than three times in the space of 2 hours. And, if they complied on night one, I needed to repeat the feat with the same foxes multiple times. Naturally, I was nervous.

Fortunately, batties are very curious. To my relief, they’ve taken to the task at hand with alacrity and enthusiasm. And to my increasing amusement I am now witnessing the ways in which that enthusiasm manifests itself. For some, they are quite content to sit nearby watching me feverishly setting up the camera and arena, eager to dig up the raisins buried in the little boxes. The fact that they hang around at all is somewhat of a minor miracle – these are wild animals and they have an entire reserve to disappear off into should they so choose. The reactions of others has been a fascinating reflection of their very unique personalities. Our highly intelligent vixen Donna, for example, lacks the patience to ever actually complete a trial, choosing instead to trash the arena like a surly teenager before stalking off, growling, into the bush. Which is why I found it particularly frustrating that Donna, not content with merely making my life difficult when she was in the spotlight, decided she needed to gate-crash someone else’s trial as well.

The fox in question, Bertha, is the mum of our current batch of pups and — despite her efforts at finding “me-time” — a difficult subject to get on her own. Two of the pups (lets call them Bane and Pestilence), have made it their personal mission to interfere as much as possible with the serious business of science. They excel at… er… endearing things like untying my shoelaces as I’m manning the camera, or rummaging through my rucksack in the middle of a trial when I can’t stop to move it. Thus, having accomplished the difficult task of getting Bertha on her own for a trial, the last thing I wanted to see midway through trial 1 was Donna. 

Bertha about the business of finding hidden rewards

 Donna’s approach was marked by a sudden business-like growl from Bertha. Now, in the past, Bertha has always been submissive to Donna, but with the arena in front of her she wasn’t having any of it. She growled meaningfully in Donna’s direction and stood her ground, one paw possessively placed in a box. Donna, being who she is, couldn’t stomach this affront and came striding towards us, intent on her mission of sabotage. Seeing that she was about to start a fight, I moved to a spot in between her and the arena to block her passage, sporting my best Gandalf-like “You shall not pass” face. Realising that neither myself nor Bertha was going to allow her access to the arena, Donna gave the only respectable response that a highly-strung vixen could give in this sticky situation. She screamed.

She literally sat down, a couple of meters from my foot, and yowled at a pitch that predicted perforated eardrums before the night was through. Now, I know this sounds like a bizarrely traumatised reaction, and I could be accused of meddling unethically with our wild animals’ emotional well-being. However, screaming is a form of self-expression peculiar to Donna. I know this, because she also does it if she happens to be around when one of the pups is getting attention from us, or if you simply aren’t paying enough attention to her directly, or whatever other slight to her person, real or imagined, is underway. I chose to ignore her (and deal with my eardrums later). Bertha too, after casting the other vixen a bemused glance, seemed happy to disregard her wailing, so I resumed filming with Bertha enthusiastically digging for raisins.

Donna continued her tirade of abuse until she realised the tantrum was not affecting us, and then carried on foraging for termites nearby, casting back the occasional disparaging glance. Well, I’d like to think that perhaps she’ll be a bit more enthusiastic about her own trial next time, but likely, she’ll just trash everything like a true drama queen. And the sad fact is, this juicy information will only be a dry blip on my computer screen when I enter the night’s data – “Trial 1 – poss soc interference (DON obs)?”