Dominant deer hinds choose best food to maintain status among peers

Washington -  When food is abundant, it seems that animals do not have to compete but it is not true at least in the case of deer hinds (Cervus elaphus).
 
A new study headed by the University of Castilla-La Mancha (UCLM), has demonstrated that even when food is in abundance, the dominant hinds still uphold rivalry and select the most nutritious food.

Deer hinds have a hierarchical organisation system: the oldest and largest hold the most dominant positions. Therefore, a nutrient rich diet benefits the more dominant hinds, who have preferential access to the best food sources.

This allows them to grow even bigger, improving their milk production and body condition.

Carried out in 2009 on the Albacete experimental deer farm, the second most important in the world (after the one in New Zealand), the experiment lasted seven days. It involved observing the behaviour of 44 deer hinds when accessing food during the first hour, their selection of food components and their nutritional composition.

The results revealed that the “dominant hinds used more time to feed during the first hour after the food was put out, they selected cereals and rejected food pellets (nutritiously low vegetable by-products),” Francisco Ceacero, lead author of the study and researcher at the department of Science and Agro-Forest and Genetics Technologies of the UCLM, explained to SINC.

The hinds chose the food according to energy and fat content. According to Ceacero, “food quality gets lower and lower the further away we move from the time in which the food is put out. In this way, the dominant hinds receive more energy in their diet whereas their subordinates do still get to eat enough but only the poor quality food that is left behind.”

Although the discussion continues on the mechanisms that drive these animals to know how to select the best food that meets their requirements every time, the scientist ensures that “the preferential selection of certain foods and the total rejection of others is clear in both diet selection studies on wild animal populations and experiments in captivity.”

The experiment combined behavioural study techniques (hierarchy and food access observation), ecological study techniques (diet component selection) and nutrition study techniques (nutritional value of each food item and the dietary intake itself).

The researchers suggest that the results are also applicable to other social ruminants like cows, sheep and goats.

The study was published in the PLoS ONE journal.