Aardvarks under threat

STUDY: HOT AND DRY CONDITIONS ARE CHANGING ANIMALS’ BEHAVIOUR Environmental stressors having a significant impact on wellbeing of nocturnal mammals.

Aardvarks top the bucket list of many wildlife enthusiasts, but few have been fortunate enough to see them – until recently. Daytime sightings of aardvarks are becoming more common in the drier parts of southern Africa. But seeing them in the daytime does not bode well.

The notoriously elusive, nocturnal mammals generally hide in their underground burrows during the day and emerge at night to feed exclusively on ants and termites. Aardvarks are widespread throughout in Africa south of the Sahara, except deserts.

But their actual numbers are not known because they’re so elusive.

To understand how aardvarks cope with hot and dry conditions, we studied them in the Kalahari, one of the hottest and driest savannah regions in southern Africa in which they occur.

Our study took place at Tswalu, a private reserve in South Africa that supports research through the Tswalu Foundation.

We equipped wild, free-living aardvarks with biologgers (minicomputers) and remotely and continuously recorded their body temperature (an indicator of well-being in large mammals), and their activity.

Each aardvark also received a radio-tracking device, allowing us to locate them regularly.

Tracking the aardvarks provided clues on how they changed their behaviour in relation to environmental stressors in the different seasons and years of our three-year study.

Our study found that in drought periods, aardvarks struggled to find food. It was difficult for them to maintain their energy balance and stay warm during the cool night, so they shifted their active time to the day. Some died from starvation.

Given the aardvark’s importance to ecosystems, these findings are a concern.

No other mammal in Africa digs as many large burrows as the aardvark. Dozens of mammals, birds and reptiles use aardvark burrows as shelter from extreme heat and cold, protection from predators, or a place to raise their young.

In many of SA’s conservation areas, temperatures have risen by 20C over the past 50 years. Further warming by 4-60C by the end of the century has been projected.

With deserts expanding across much of Africa, climate change might threaten the aardvark itself as well as the many animals reliant on aardvark burrows.

During typical years, aardvarks were active at night and were able to regulate their body temperature between 35-370C.

However, this pattern changed during two severe summer droughts that occurred in the Kalahari during our study. During the droughts, aardvarks shifted their activity to the daytime and their body temperature plummeted below 30°C.

Using remotely-sensed vegetation data recorded by Nasa satellites and our own camera trap footage and logger data, we showed that these changes in body temperature and activity of aardvarks were related to the availability of grass, on which their ant and termite prey rely.

When grass was scarce, the ant and termite prey became inaccessible to aardvarks, preventing them from meeting their daily energy requirements.