While hibernation is typically associated with icy northern hemisphere conditions, Africa’s first black evolutionary physiologist is making fascinating discoveries about this phenomenon in South Africa.
Dr Kwezi Mzilikazi’s groundbreaking research on small mammals — so chosen because they are unable to escape external conditions through migration — has put her on the global science map.
“When you do something obscure, people notice, even if it’s not all that glamorous!” she said. Be that as it may, the Nelson Mandela Metropolitan University zoology senior lecturer, along with the postgraduate students she is supervising, is conducting research that has never been done before — and the results are surprising.
For instance, did you know that woodland dormice in the Great Fish River area lower their body temperature to as little as two degrees Celsius to survive the worst of winter?
“This is groundbreaking as Africa has always been thought of as being warm. In the northern hemisphere, Arctic ground squirrels have been known to decrease their body temperature to -3 degrees. But this (phenomenon) is unexpected in Africa.”
The tiny dormice go into a state of torpidity, which can last for days. “They only weigh 25g. If their fur was long and thick (to keep them warm), it would impede their movements. The only other way to generate heat would be to eat more, but when it gets cold, insect availability goes down. Decreasing their body temperature is a survival tactic.”
One of Dr Mzilikazi’s students has in the last three weeks discovered a similar response in bush babies in the Limpopo area. ‘This is huge news since no primates, besides lemurs in Madagascar, have been known to become torpid.”
Dr Mzilikazi is also concerned about how the advent of global warming will affect hibernation patterns, and is already carrying out experiments to monitor how temperature increases affect animals.
“It’s important to describe what is going to happen. If you lose one species, it affects an entire ecosystem.”
Evolutionary physiology, which seeks to understand how animals function and how this impacts on their ability to reproduce — the ultimate measure of success in the wild — captured Dr Mzilikazi’s imagination quite by chance.