In times of need, gazelles shrink their organs
During periods of severe drought, the goitered gazelles (Gazella subgutturosa) living in the Arabian Desert can significantly reduce their organs in order to reduce their water losses.
The heart and liver in particular shrink when there is a lack of food and drinking water: This lowers the metabolic rate and thus the gazelles' need for oxygen, they have to breathe less often and consequently lose less liquid in the form of water vapour. According to biologists led by Stéphane Otrowski from the Saudi Arabian National Wildlife Research Center, similarly low water losses have not been measured in any other desert-living ungulate that has been studied to date.
On the other hand, the intestine does not change during times of crisis: Since it uses a quarter to half of the available food and converts it into available protein, it must be fully functional immediately when the gazelle encounters food. In addition to energy, the vegetation also serves its drinking water needs, as there are only a few sources in the Arabian Desert. And the brain – as the largest energy consumer – does not lose weight during the periods of deficiency. Instead, the researchers discovered that the animals store comparatively large amounts of fat there. This is probably how the gazelles secure the metabolism in their thinking organs even during times of extreme need.