This week on Dispatches from the Field, we are happy to welcome Zach Mills, a graduate student at the University of the Witwatersrand in Johannesburg, South Africa! To learn more about Zach, check out his bio at the end of the blog.
Field work in Africa never behaves itself. It consists of perpetual improvisation because things never go to plan. It demands adaptability, a bit of nerve and resilience. The truth is that fieldwork is what happens when everything functions smoothly; the rest of the time you’re trying to make fieldwork happen. Fieldwork is a lesson in patience and mental fortitude, and this is precisely why we field people love it.
I study thermoregulation in spotted hyenas (Crocuta crocuta); specifically, I study the influence of metabolic heat production on hunting in endurance hunters. That’s right – endurance hunter; hyenas are effective cursorial hunters that capture prey by running it to exhaustion.
In May 2019, I arrived at my field site in northeastern Namibia with eight days to re-capture eight spotted hyenas in order to remove GPS collars I had deployed a year prior. My plan was simple and effective: use a carcass to bait the clan into a suitable area and blast a series of prey vocalizations followed by a series of hyena vocalizations to get the clan’s attention. Wait and thou shall be rewarded with scores of hyenas. It usually takes a day or two to congregate the clan, but it has historically been foolproof. While spotted hyenas are competent hunters, I’ve never known them to turn down a putrid carcass per gratis.
Zach takes a minute to pose with a lion carcass in Khaudum National Park, Namibia (Photo credit: Hans Rack)
Two things work in my favor when it comes to hyena aggregation at a bait site. First, spotted hyenas have amazing noses, far better than a bloodhound. With a favorable breeze they regularly beeline 10 km directly to a bait site. Second, they regularly patrol their home ranges in small coalitions. In a clan of 40 individuals, the chances of a patrolling group intercepting the scent of the bait and alerting the clan to the complimentary bounty is extremely high.
However, one thing generally works against me: hyena astuteness. When I started studying hyenas, I considered myself to be the more intelligent species and therefore assumed the odds of successful capture were in my favor. I have since reconsidered this.
Last May, I had returned to the field to retrieve the devices at the precise moment the hyenas were all where they were supposed to be – their natal home range.
However, the first night I put the bait out, nothing. Second night, again nothing. On the morning of the third day, I called the collar manufacturer to get recent locations for the study animals. Seven of the eight were 15 km to the north; the eighth (a male) was moving east towards Botswana. I disregard a recommendation from the collar manufacturer to use a helicopter to capture that male and persisted with baiting and calling. Third night, nothing. I called the collar company back and was informed that the rogue male was well into Botswana moving toward the Okavango Delta. The misfortune continued the fourth and fifth nights. At this point, I had only 72 hours to capture 8 hyenas.
Zach performs a physical examination on a sedated spotted hyena (Crocuta crocuta)
Lucky for me, a helicopter pilot in camp for other projects took pity on me and offered me an hour of fly time at sunrise and another hour at dusk to locate the wily hyenas using their radio collar frequencies and capture them. This was far more effective than my ‘foolproof’ strategy; the first hyena was tranquilized by a dart administered sedative shortly after sunrise. We captured a second individual that morning and a third in the evening. I was hit with a wave of optimism.
Zach attempts to locate a study animal in Khaudum National Park, Namibia.
The next morning, horizontal rays of the early Kalahari sun cut through the bush as the helicopter rotors began to roar. The shadows cast by the acacia trees are deceptively long in the early morning hours, making it feel like you’re flying over an endless game of jackstraws.
Looking like a vagrant who had escaped from an international detention center, with collar frequencies scribed on my arms, holes in my down jacket, and a face weathered by endless desert sand, I was after one particular adult female that morning: #2746. Last year, #2746 was 210 pounds of impossible to chemically immobilize bad attitude. She was the boss of the bush, the matriarch of the motherland, the Queen of the Kalahari.
I hate to anthropomorphize, but #2746 is an animal of note. I had spent the past year psychologically preparing for our next encounter. True to her mysterious ways, it was a telemetry exercise from hell locating her that morning. Ultimately, I understood why: she’d peek her head out of a shallow den just long enough to send a few radio signals my way before vanishing underground.
But eventually, we caught her off guard, and a well-placed dart found her rump. A chase ensued, and she led us directly to a second den site. We gained altitude to let her fall asleep before she descended deeper into the den.
Zach recovering #2746 from a den (Photo Credit: Markus Hofmeyr)
After ten minutes, we landed, and I peered into the den. #2746 seemed comfortably asleep a meter from the surface. I descended into the den in with a rope in my teeth to recover the half-asleep hyena. I planned to loop the rope around her shoulder, shimmy my way out, and drag her out with the help of two people.
As I looped the rope around her shoulder, she blinked. And then she lifted her head. And then she growled.
Our faces were 10 centimeters apart and I could tell from her breath that she had no reason to visit my bait because she had been enjoying something equally putrid all night long. She lifted her front leg, and the rope slipped from her shoulder. She then advanced in my direction and as the rope slipped to her wrist, I elected to evacuate the den.
Equally startled, we exited the den simultaneously. Now #2746 was tethered to the other end of the rope wrapped around my arm. I tried to act casual while walking behind her, imagining myself out for a morning walk with Canis familiaris. However, I would be remiss if I failed to acknowledge the feeling of impending doom one experiences while walking an irritated hyena through the bush. Keep it together Zach, she smells the fear!
I was able to keep #2746 on the rope long enough to administer a second sedative dose. She finally fell asleep peacefully and we fitted her with a new GPS collar, and sent her on her way. I’m actively preparing myself for our next encounter.
Zach is a self-proclaimed field junkie; he views his body as an all-terrain vehicle specialized in getting him far from the beaten path. He explores the world through his passion for wildlife research, conservation and sustainable resource management. His research focuses on the physiology of large carnivores but he enjoys storytelling and sharing his adventures from the field with public audiences. He prefers his meals cooked on an open fire, his clothes ripped and his beard untamed. He’s a field biologist.