Some plants rely on birds or the wind to carry their seeds far and wide, while others have evolved prickly seeds that can hitch a ride on the coat of a passing animal. But the Argania trees of Morocco have a different dispersal method: climbing, spitting goats.
Some of the local goats have developed a distinctive approach to grazing during dry periods: They climb up in the thorny branches to get at the tree’s leaves and fruit, sometimes with help from herders. The goats are bigs fans of the fleshy exterior of the fruits, but they couldn’t care less about the large, hard seeds. It’s always been assumed that the goats just swallow the seeds, which would pass through the digestive tract. The seeds are then gathered so valuable argan oil, which can be used both in cooking and for cosmetics, can be extracted. But new research suggests the goats aren’t swallowing the seeds after all.
The researchers, from Spain’s Doñana Biological Station, were skeptical of the stories about Argania seeds in goat poop (they’re awful big), so they decided to test their hypothesis on some real subjects. They fed 29 Spanish domestic goats a bunch of different kinds of fruit, including ones from fan palm, common hawthorn, Mediterranean hackberry, olives, and locust bean, and watched what happened to the seeds.
Some of the smaller seeds went through the full digestion process, but the goats spit out many of the large ones. The researchers write in their report that this isn’t actually weird behavior—they’ve observed sheep and deer spitting out seeds as well. They’ve determined that it’s far more likely that the daring, tree-climbing Moroccan goats spit out their seeds. If the behavior is as common as the researchers suggest, it’s possible this is an important but overlooked form of seed dispersal—one that may be critical for some ecosystems and plant species.