Mating season plays havoc with the blue wildebeest’s sleeping patterns. In fact, it is believed that during this time they don’t sleep when females are around, using the time after the two- to three-week-long mating season to play catch-up.
These findings form part of a new study on the sleeping habit of the prey animal by Wits anatomical science lecturer Dr Illke Malungo, published in February.
It found the ungulate only gets about 4.5 hours of sleep a day.
This is one of many animals Malungo will study to inform a greater body of work that will look at different classes and species to document patterns of sleep.
She hopes the revolutions of sleep in animals will help us learn why we sleep and how human sleep works.
It’s such a fascinating study – if we can understand the animal better then perhaps we can help conserve them better
“It’s such a fascinating study – if we can understand the animal better then perhaps we can help conserve them better.
“But I’m really interested in the sleep field, and the hope is that these studies can inform us a little bit more about ourselves. Usually rats and mice are used for this research, but they are not necessarily the best animal to compare [with the human brain].”
Tests on the wildebeest were conducted using electrodes surgically placed on the surface of the brains of two wild male blue wildebeest from the herd in the Dinokeng Game Reserve in Gauteng.
Before this, test studies of the animal were conducted visually or on animals in captive environments not natural to them.
Malungo said visual studies had suggested the animal slept for about two hours longer, but the actual science shows they get 28 minutes of REM (rapid eye movement) sleep and 4.2 hours of non-REM sleep.
According to the SA Society of Sleep Medicine, REM is a phase of sleep where our eyes move rapidly and our muscle tone is low. In this phase we are able to have vivid dreams. Non-REM sleep is a light sleep during which one can be woken easily but one’s muscles begin to relax. Wildebeest may be walking or moving during non-REM sleep.
Malungo said she also chose this animal because of its fascinating annual migration between Tanzania and Kenya, during which more than 1.5 million of them will go in search of food and water.
“We’ve done similar studies on buck, but I thought what about the migration and the effect it must have on sleep.”
As an example she said the study found that most of their sleep occurred from 3am until dawn.
This could be a way to prevent predators. Lions hunt at night from around midnight to 2am. After that they rest, so it could be that it is a safer time for the wildebeest to rest
“This could be a way to prevent predators. Lions hunt at night from around midnight to 2am. After that they rest, so it could be that it is a safer time for the wildebeest to rest. Just before dawn is also the darkest time so they cannot be seen as easily.
Prof Paul Manger, who also took part in the study, said the most interesting finding in his research was the amount of REM sleep the animal got as it upheld the theory that domesticated animals had more REM sleep.
The wildebeest had about 30 minutes of REM sleep – 6% of their sleep time, similar to the amount other non-domesticated herbivores got. Domesticated animals got more REM sleep – such as the cow’s 19%.
“This is interesting because it appears a similar thing has happened with humans.”
He said REM sleep in humans was 24% of our sleep time, but in chimpanzees – most comparable to humans – REM sleep was 15%.
Malungo is now seeking funding for her next project, which will look at sleep in lions.
“I am so keen to see what is happening in lions that are said to get about 22 hours of sleep a day. There is still so much to explore. Nobody really knows why we sleep – though there are theories. The only reason we know we sleep is because we get tired.”
– Sunday Times Daily