Elephants need large quantities of water for drinking and for staying cool
Finding water is often a good start for tracking elephants. There are many reasons why elephants are never far from water.
Every day, elephants in the wild might travel tens of kilometres for water. This need for water has shaped their ancient routes of seasonal migration. Certainly among African elephants, the oldest elephant, the matriarch, leads the herd. Thanks to an exceptional memory, she may be the only one who knows where water remains in a drought. Elephants can also smell water from several kilometres. They will even dig for it if necessary. Although elephants obtain water from the green plants they eat, they still need to drink up to 200 litres per day from pools, rivers, waterfalls or even hoses. They do this by siphoning around 10 litres of water into their trunks and then propelling it into their mouths. Infants drink directly via their mouths as it takes several years to master their parents’ skills.
Where possible, elephants like to bathe for about an hour each day, and they use their trunks to squirt water over themselves. Bathing is important to elephants because, in order to preserve their levels of hydration, they don’t sweat to cool down as humans do. They also have clever adaptations to help them stay cool for hours after leaving the water. Water gets trapped between the wrinkles in their skin, via capillary forces. This increases the surface area of their skin and hence the time over which water evaporates, removing more heat from their bodies. Their long, sparse body hair also entraps water and conducts heat away from them. Infants are hairier than their parents, presumably because they are smaller, so would otherwise get overheated faster.
Bathing keeps elephants clean, especially playful ones who love mud. Although mud is cooling and protects against biting insects, the above adaptations work best on clean skin. With age, an elephant’s skin condition deteriorates – it becomes baggy, wrinkly and dried-out. For domesticated elephants, this problem can be managed by Kwan Chaangs (elephant carers, or mahouts) who wash their elephants daily, using brushes and sometimes natural soaps. This exfoliates and hydrates the skin, maintaining its functionality. Washing also minimises the risk of infections, common in wild elephants, by removing parasites, excrement and mud, particularly from the ears and eyes.
Elephants love water. Infants splash and climb on their mothers; juveniles dive, roll and playfight. Water also enables adults to meet and socialise, while older elephants generally stay still and relax. Elephants are even capable swimmers from a few months old. Their fatty bodies float, tipping their heads downwards, but they can swim for hours breathing normally. Not only do their trunks act as snorkels; elastic tissue around their lungs accommodates their increased blood pressure underwater (already high in large mammals).
These unusual characteristics appear early in fetal development, revealing possible aquatic ancestors. Of modern species, elephants are genetically closest to Sirenians (manatees and dugongs). After splitting from Sirenians, elephants’ ancestors probably became semi-aquatic. Chemical analyses of 37-million-year-old fossils reveals these creatures ate freshwater plants, probably spending lots of time in water. The Earth cooled and dried at the end of the Eocene period (34 million years ago), probably forcing elephants’ ancestors onto land, where they adapted to a terrestrial life. This would explain elephants’ unique morphology and why young elephants instinctively learn to navigate water through play.
At STEF’s Elephant Veterinary Centre near Khok Kloi, where we hope to be ready to receive our first patients in the next month, we have had to dig deep to secure a fresh water supply throughout the year. Creating the elephant pools was quite a task, as you can see from our three news stories: news 1 news 2 and news 3
Swimming elephants- http://www.42evolution.org/elephants-aquatic-ancestors-just-below-the-surface/
Elephant ancestry- http://news.bbc.co.uk/1/hi/sci/tech/7347284.stm