Tanja van de Ven, Andrea Fuller & Tim Clutton-Brock
The survival of meerkat pups in the arid Kalahari of southern Africa has decreased over the past 20 years, and it looks like climate change may be to blame.
Meerkats live in groups, like many other arid-adapted animals, and it is thought that the benefits of helpers in the group allow these animals to thrive in harsh environments. We were surprised, therefore, to find that increased provisioning of food to meerkat pups by adults in the group was not sufficient to buffer the pups against higher heat loads associated with climate change.
In the Kalahari, air temperatures have steadily increased over the past two decades, such that mean daily air temperature is now 1.5°C higher. We found that the amount of body mass that meerkat pups gain each day decreased as daily maximum air temperature increased. That decrease in daily mass gain occurred despite the adults feeding the pups more food items on hotter days, and was associated particularly with a decrease in body mass gain on hot afternoons.
We believe that the results can be explained by higher body water loss on hotter afternoons. It is known from laboratory experiments that meerkats in the heat lose substantial amounts of water through evaporative cooling. Small meerkat pups exposed to high soil temperatures and heat from the sun are likely to dehydrate rapidly on hot afternoons. Dehydration, in turn, is associated with breakdown of muscle and reduced growth, which can explain why the meerkat pups’ overall body mass at the age of three months also has decreased over time.
Meerkats rarely drink, obtaining water through their diet instead. Continued increases in air temperature associated with climate change, as well as reduced or variable rainfall in the region, are likely to make it even harder for them to meet the demands of keeping cool and obtaining sufficient food.
The study adds to the growing evidence that climate change is already having severe consequences for the welfare of many mammals, including other iconic species like the aardvark and African wild dogs.