When we finally get to bed and close our eyes at night, our body and mind embark on an incredible journey through different sleep stages. They first begin to relax, preparing themselves to move into sleep mode. We then graduate into a light sleep, when breathing slows down further and the body temperature drops. A specific pattern in the brain begins, and scientists believe that it is this the stage when the brain organises memories. This takes us to the next level, where we are in the deepest sleep. While our body rests, it is also allowing it to heal itself. The fourth and final stage is REM, or Rapid Eye Movement, when the mind lets us enter into the world of dreams. While our body may be inactive, our brain is wide awake, as it is in the day. These stages tend to repeat four to five times at night, with each lasting anywhere between 90 and 110 minutes.
Unlike humans, elephants have a special way of resting — they can nap while they are standing up! This way, they can wake up quickly to respond to any sense of threat. It is only when they are lying down do they experience the REM sleep stage. Wild elephants only enter this stage once every three to four days, since they are constantly required to feed and remain alert. Scientists wonder if this means that elephants dream less? REM has been associated with strengthening memories, so how do elephants, known for having extraordinary memory, preserve theirs? It’s a puzzling question that researchers are still trying to solve!
At Wildlife SOS, observing elephants as they sleep offers a revealing insight into their sleep pattern. Caregivers have noticed how sometimes, while sleeping, their feet twitch, which is a sign of them being somewhere between non-REM and REM stages of sleep. Caregivers often try to decode if they’re dreaming of a refreshing bath or a peaceful evening walk! Another fact about elephants is that as they grow older, their sleep duration reduces and becomes more sporadic. Calves, much like human babies, sleep longer and frequently, and studies suggest they require more REM for their brain development.
Sleeping Patterns: Wild vs. Rehabilitated Elephants
Feeding Needs — To cater to their massive size, elephants in forests spend 2/3rd of their day feeding on leaves, fruit, and grass, consuming nearly 150 kg of food daily. Their movement to feed compromises their hours of sleep. In contrast, elephants under rehabilitation have a nourishing food supply readily available, which allows them to dedicate more time to sleep.
Predator Awareness — In the wild, elephants remain alert to diverse threats that include predators like lions or sudden negative encounters with human beings. Some members of the herd take turns to sleep while others stand guard. The matriarch, responsible for the herd’s safety sometimes goes without sleep for days, ensuring that her group is secure. These situations are absent for elephants under long-term rehabilitation.
Environmental Conditions — Factors like temperature, season, and habitat influence migration patterns of wild elephants, which also affects their sleeping behaviour. However, for elephants under care, these factors do not pose any obstacles since seasonal management protocols are implemented for them.