Despite having adapted to life in extreme heat, a new study published in the journal Royal Society Open Science has discovered that elephants lose a surprising amount of water on hot days. After measuring the elephants’ output, researchers estimated that some elephants were losing up to 10 percent of their body mass when temperatures were high, indicating how important adequate water consumption is to their survival. The finding is cause for concern as a warming Earth is already depleting the water available to elephants, and competition for resources will likely increase the conflict between human and elephant populations.
To investigate the effect of temperature on water loss, a team at the North Carolina Zoo led by Corinne Kendall used deuterium to measure how much water elephants were losing. Deuterium, also called heavy hydrogen, is a harmless isotope of hydrogen that disperses in body water and its concentration can be measured by taking blood samples. Over 10 days, the team took samples and tested for deuterium strength to see how much had been eliminated from the animals’ body water.
An analysis of the concentrations revealed that the elephants were losing far more water in a day than was expected. On cool days ranging from 6 to 14°C (43 to 57°F), they were losing around 325 liters per day. On hot days above 24°C (75°F), this number jumped to an average of 427 liters with some losing as much as 516 liters. To put that into context, that’s about the same amount needed to fill two bathtubs. The stats for hot days amount to around 7.5 percent of their body mass or 10 percent of their total body water.
Though only a small number of captive elephants were studied, the sheer volume of water lost by the elephants on warm days demonstrates why replenishing fluids is such a make-or-break demand for these animals. Elephants can mediate these losses by altering metabolic processes, but the researchers state their findings show they are at risk of fatal dehydration if they go without water for more than two days.
In an ever-warming world, this is bad news. Elephant populations are already under threat and once you add into the mix watering holes drying up and a reduction in water-rich plants the outlook grows bleaker. A mass die-off event this year that was claimed by the Botswana government to be the result of natural toxins, though others said human conflict was to blame, saw the loss of hundreds of elephants. Whether the elephants were put at risk due to drinking from contaminated pools or competing with humans for resources cannot yet be concluded, but either way it paints a concerning picture for a species that so desperately needs access to clean, conflict-free water.
[H/T: Science Magazine]