How Tree-Climbing Goats Make the Moroccan Desert Bloom

A new study in the May issue of the journal Frontiers in Ecology and the Environment by Spanish ecologists has found that tree-climbing goats in Morocco perform a variation of the seed dispersal effect called endozoochory, which is mutually beneficial for both the goats and the trees.

Endozoochory is the process by which seeds pass through a ruminant's entire digestive system and are excreted, thereby being dispersed to wherever the animal happens to be. This time, however, the goats are ruminating their cud and then spitting out the big seeds before they pass all the way through.

As reported by Science Daily, domesticated goats in the dry deserts of Morocco learn how to climb trees when they are young, sometimes with the help of local herders. They are searching for food, and end up eating and chewing the leaves and fruits of these native argan trees. The goats, however, seem to not like the particularly large seeds of argan trees, because they spit them out onto the ground while they are grazing.

In the study, entitled "Tree-climbing goats disperse seeds through rumination," the researchers describe how goats, like cows, sheep and deer, are ruminants, meaning they acquire nutrients from their food by fermenting it in a specialized stomach before digesting it. So while ruminating over their cud, the goats spit out the argan nuts wherever they have wandered, which in turn disperses the seeds. Seeds that have gained distance from their parent tree are more likely to survive.

Researchers have witnessed this spitting out of seeds by other ruminants such as sheep, captive red deer, and fallow deer, suggesting that perhaps it is a more common process of seed dispersal than previously thought.