Tree-Climbing Goats Disperse Seeds by Spitting

But the goats don’t like the large seeds. Like cows, sheep, and deer, goats re-chew their food after fermenting it for a while in a specialized stomach. While ruminating over their cud, the goats spit out the argan nuts, delivering clean seeds to new ground, wherever the goat has wandered. Gaining some distance from the parent tree gives the seedling a better chance of survival.

This novel seed dispersal effect is a variation on the mechanism ecologists call endozoochory, in which seeds more commonly pass all the way through the animal’s digestive system and out the other end (or sometimes through two digestive systems). The authors suspected that reports of goats dispersing argan seeds by this more common mechanism were mistaken, because goats do not usually poop large seeds.

The researchers have witnessed sheep, captive red deer, and fallow deer spitting seeds while chewing their cud, and suspect this spitting variation on endozoochory may actually be common – and perhaps an essential route of seed spread for some plant species.

Contacts and sources:
Liza Lester
The Ecological Society of America

Citation: Miguel Delibes, Irene Castañeda, José M Fedriani. (2017) Tree-climbing goats disperse seeds during rumination. Front Ecol Environ 15(4): 222-223, doi:10.1002/fee.1488