Drinking behaviour of llamas (Lama glama) in choice tests for fresh or saline water

Abstract

In the native region of South American camelids (SAC), the High Andes, llamas (Lama glama) face the dual confrontation with seasonal water scarcity and the risk of water salinization. The present aims are to provide more insight into drinking behaviour of llamas and their behavioural strategies in discriminating and selecting different concentrations of saline water in choice tests. Twelve adult non-pregnant female llamas with an average initial body weight of 140 kg ± 20.6 kg were kept under controlled conditions in individual pens. After a control phase (1 week) providing only fresh water, two choice tests were consecutively conducted: (1) a pairwise preference test (3 weeks) offering the choice between one bucket with fresh water and another with stepwise increasing NaCl concentration (0.25, 0.5, 0.75, 1.0, 1.25, or 1.5%) and (2) a free-choice test (3 weeks) offering six buckets simultaneously with concentrations of 0%, 0.25%, 0.5%, 0.75%, 1.0%, and 1.25% NaCl. Chopped hay, water and a mineral lick were provided for ad libitum intake. Records were kept on body weight, body condition and daily drinking water intake. Individual 24-h video recordings (23–24 per animal) were analysed for drinking duration, frequency of drinking and testing, the latter being defined as drinking lasting maximum three seconds. Body weight and body condition remained constant. Overall, a low drinking frequency was observed, indicating an adaption to water scarcity. During the control phase, the pairwise preference and the free-choice test, the daily drinking duration (p = 0.019) and frequency (p < 0.001) increased significantly averaging 162, 238 and 263 s, and 3.71–5.17 and 7.60 bouts, respectively. Similarly, the testing-to-drinking frequency ratio increased (p < 0.05) averaging 0.26, 0.35, 0.79 in phase 1, 2 and 3. Most drinking bouts occurred during the daytime (83% of drinking bouts) and followed a biphasic rhythm with peaks in the morning and the evening. Llamas showed a remarkable tolerance of saline drinking water, similar to goats. Furthermore, llamas demonstrated their capacity for behavioural adaptation when more choice options were offered by changing their drinking pattern, while maintaining their diurnal rhythm of water intake. Decision-making was based on testing of solutions which increased considerably when more choice options were offered in the free choice test. Nevertheless, the llamas maintained a high intake of saline water. The low drinking frequency of the llamas might hamper their memory formation and discrimination learning when more than two samples are offered simultaneously.