Interview with chief aardvark researcher, Dr Sarah Edwards
2 Aardvarks is supporting research into the effect climate change is having on aardvarks, being carried out by the AfriCat Foundation in Okonjima Nature Reserve, Namibia. We wanted to know all about it, so we talked to chief aardvark researcher Dr Sarah Edwards.
How did you become interested in African wildlife?
As a child I was always obsessed with animals and wanted to be a vet. However, my path led me to study Animal Behaviour for my BSc, MSc and PhD, which I think was definitely a better choice for me than veterinary medicine. African wildlife became an interest for me once I’d visited South Africa for the first time as part of my degree, seeing the wide variety of species and research opportunities sparked what has since became a career.
Dr Sarah Edwards with an aardvark
When and where did you start researching aardvarks?
I first came to Namibia after my degree to gain field experience, and spent a year researching ground squirrels. I then starting working with brown hyaenas and since then the majority of my work has focused on large carnivores. I started working at AfriCat, based on the Okonjima Nature Reserve, north-central Namibia, in January 2018 and focused on starting a brown hyaena research project. The aardvark research started quite recently in June 2019 and whilst the learning curve has been steep and the challenge large, working on a totally different species has been really enjoyable.
Do you know how many aardvark burrows there are in Okonjima?
Lots!! I can’t say for certain how many, but there are burrows everywhere over the 200km2 of Okonjima. Aardvarks use different burrows nearly every night so you often drive in an area and see a fresh aardvark burrow that wasn’t there yesterday.
How many aardvarks are there in Okonjima?
Because aardvark do not have individually unique markings, like a leopard, where each individual has a unique spot pattern, it is difficult to know how many we have here. Last year, during one of the worst droughts in living memory, we lost a lot of aardvarks to starvation and predation by leopards and brown hyaenas. So, our population has decreased quite significantly.
What is your favourite fun fact about aardvarks?
During times of energy deficiency, they exhibit heterothermy, which means they are able to switch from endothermy (physiological generation and regulation of body temperature by metabolic means, like all mammals) to ectothermy (regulation of body temperature depends on external sources, such as sunlight or a heated rock surface, like a reptile). Previous studies have shown internal body temperatures can range from 33.4–37.2°C.
Why are aardvarks interesting?
Aardvarks are a keystone species and ecosystem engineer; the burrows they dig provide thermal refuges for the wider wildlife community, for example, pangolin make use of aardvark burrows on a daily basis and at the moment, we have lots of warthogs using aardvark burrows to rear their piglets in. They only eat ants and termites, species which experience population crashes during droughts. This makes the aardvark vulnerable to climate change impacts. As they are so important for the ecosystem, losing them could have cascading community impacts.
Aaardvark with VHF ear tag
What are you trying to find out in the research?
Our aardvark research is focusing on the potential impacts of climate changes on aardvarks outside of the Kalahari. To date, we know in the Kalahari Desert, which represents the edge of aardvark range and an area particular vulnerable to climate change impacts, aardvarks experience mass die offs during droughts, which are predicted to become increasingly common with climate change impacts. We are repeating certain parts of previous research to see if aardvarks in higher rainfall areas are also experiencing negative climate change impacts. If they do, it means the future for the aardvark as a species could be threatened as climate change impacts increase.
What behaviours would indicate them adapting to the new changes in the environment?
We’ve seen aardvarks basking outside of their burrows during the day during the drought. We believe this is a response to the lack of food, causing them to become so energy deficient that they need to bask in the sun to help maintain their internal body temperature – it is the change to heterothermy. It is an energy saving tactic. Unfortunately, this behaviour leaves them very vulnerable to predation and ultimately, during extreme droughts, this behavioural change is not saving them enough energy and many aardvarks still die from starvation.
How long do you plan to do the research?
We will keep going with our aardvark research, we need to compare aardvark behaviours, activity patterns and body conditions in both good and bad rainfall years.
How do you decide which burrow to observe?
When we tag an aardvark, we are able to track it using a telemetry device. We will usually go out during the morning and track the aardvark to the burrow it is using that day and set a camera trap up outside. This allows us to record if the aardvark is basking and what time it emerges from the burrow. We can later link emergence times to environmental variables such as temperature.
An aardvark burrow
How do you do this with the VHF ear tag, Camera Trap and Temperature Logger?
With the VHF ear tag we will be able to attach this to an aardvark and start tracking it during the day to the active burrow. We will then use the camera trap outside the active burrow to record any basking behaviour and the time of emergence. We are using the temperature loggers to compare temperatures inside burrows with outside and see how the burrows act as thermal refuges for all the species which use them, both in summer and winter.
What is a VHF ear tag? How does it work?
VHF stands for very high frequency. The tags emit a very high frequency pulse sound, each tag producing a pulse at a different frequency, like different radio stations using different frequencies. We then use a telemetry device, set at the specific frequency of the tag, to track the animal. The telemetry antenna can be used to detect the direction of the tag, as you get closer to the tag, the pulse becomes louder.
How do you attach the VHF ear tag?
It is like a cow ear tag that farmers use to number their animals; we punch a small hole in the ear and attach the tag. Unfortunately, aardvarks cannot wear collars; their skin is sensitive and becomes sore and infected as the collar rubs. Previous research has used internal VHF implants, which need to be sewn into the abdominal cavity of the animal. We felt this was too invasive and rather went with a VHF ear tag, and it seems like we are the first to try this approach.
Fitting the VHF ear tag
Can the aardvark still hear with the ear tag attached?
Yes. Aardvark ears are very big and their hearing is very good. The tag is attached to the edge of the ear so it isn’t blocking the ear in any way. From experience tracking them, they can still hear you coming and if you accidently step on a twig they quickly run away.
Does the ear tag cause the aardvark any discomfort?
We’ve spent many hours tracking the aardvarks at night and not once have we seen them to show signs of discomfort, they just seem to totally ignore the tag. Aardvark welfare is our first priority, so if we had seen signs of discomfort, we would have removed the tag immediately.
Why is it called a camera trap?
It’s a good question, but actually they don’t trap animals at all. They just take a photo of an animal when it passes in front of the camera. Most of the time the animals don’t even realise they are having their photo taken.
When and how does the camera trap capture the Aardvarks?
The cameras work with movement and heat, when something hotter than the background moves in front of the camera, they take a photo which has a date and time stamp on it. Because aardvarks are quite big, the camera traps record them reliably when emerging from their burrows. All photos are stored onto an external SD card and we would exchange the SD card with a new one to be able to download the photos.
What do the temperature loggers do?
They record temperature and relative humidity. We are setting them to a high resolution of taking measurements every 10 minutes. The nice thing about these loggers is they have a replaceable battery so we can use them on a continual basis.
How do you use the temperature loggers?
We place them deep inside the burrow (with the help of long BBQ tongs!) inside a metal protective cage to stop the hyaenas eating them (hyaenas love plastic) and the device will record the temperature inside the burrow. To compare this to the outside temperature, we place another logger immediately outside the burrow in the shade. This paired design allows to us to make direct comparisons between the two areas and see how much cooler in summer and warmer in winter, the burrows are than outside of the burrows.
The equipment being used in the study
Is the equipment connected to a computer?
The VHF ear tags unfortunately are not connected in this way. We would have ideally liked to have used GPS ear tags which record the position of the animal every hour and then automatically upload this data to a computer. However, the very small size of GPS tag we would have to use for an aardvark ear would use solar for power to save on using a heavy, big battery. With aardvarks being nocturnal, solar powered devices just won’t work. So, we have to actually go out into the field and track the animals to be able to record spatial data. We’ve found we can get relatively close to the aardvarks, within 15 meters. They seem to also rely on scent quite heavily, so as long as you are downwind, you can get quite close. Their eye sight is poor and I’ve had experiences where the aardvarks have walked within two meters of me, before picking up my scent and getting a fright.
How can you differentiate aardvarks from each other?
We can’t really, unless they have distinctive rips in their ears, which seems to be quite common, especially for older aardvarks. Younger animals, without ear rips are difficult to differentiate.
What are the most interesting/new finding so far?
I think our recent observation, in which the camera trap recorded two aardvarks coming out of the same burrow was really interesting. There are anyway so few studies on aardvark, but the literature always says they are solitary, so this was a surprise. Potentially the two had been mating. Otherwise, seeing the aardvarks here switching to day time activity and basking outside their burrows during the drought was interesting, but at the same time worrying; it seems climate change impacts are negatively impacting aardvarks across their range and we could really be looking at aardvark extinction if global temperatures continue to rise.
A video caught by the camera trap
Can I help too?
Yes, please visit the AfriCat website https://africat.org/aardvark-research/
2 Aardvarks is supporting the AfriCat research by funding the cost of the camera trap, VHF ear tag and pair of temprature loggers. We really look forward to hearing more about the findings as the study progresses.