How tree-climbing goats plant new trees
If you’re a goat enthusiast it’s probable that you already know of the curiously awesome phenomena of Morocco’s tree-climbing goats – and anyone who has never seen this wonderful weirdness before, should. It’s such an unlikely scenario, these decidedly hooved land animals perched atop branches like dainty birds.
Goats are fabulous and incredibly agile – and in arid places with little forage, they will climb straight to the top of trees to chomp away on what may be the only available greenery around. Likewise, when they’ve gobbled up all the fallen fruit from the ground, the hungry things will march right up the tree to find some more.
It’s a sight to behold, for sure, but beyond entertaining masses of YouTube viewers, tree-climbing goats provide another important service as well – they are agents of seed dispersal for the trees they climb. In the case of Moroccan goats, argan trees.
It’s not news that animals ingest fruit and then deposit the seeds elsewhere after carrying them around in their stomachs for a while. But a new study finds that there’s another mechanism going on as well, one that hasn’t been researched very much, if even acknowledged at all.
The goats spit the seeds out after ruminating.
Finding this out was in fact the aim of the research, inspired by the realization that excreting such large seeds (acorn-size) would be challenging. “The purpose of our research was to verify that goats regurgitated the nuts of argan fruits while ruminating,” write the authors, “as we postulated that this could be a potential dispersal mechanism for large seeds.”
And they’re not the only seed spitters, notes the study:
In southern Spain we have observed sheep, captive red deer (Cervus elaphus), and fallow deer (Dama dama) also spitting out seeds during rumination, and Yamashita (1997) described parrots in Brazil collecting clean palm seeds in places where cows had gathered and ruminated during the night, but did not consider the implications for seed dispersal.
If spitting viable seeds is widespread among ruminants, as the researchers suggest, its ecological relevance could be significant.
“Importantly, the seeds of some species are unlikely to survive passage through the ruminant lower digestive tract so that spitting from the cud may represent their only, or at least their main, dispersal mechanism,” the study concludes. “It is therefore essential to investigate the effectiveness of this overlooked mechanism of seed dispersal in various habitats and systems.”
Which clearly is another way of saying that the researchers want to spend more time watching goats climb trees, right?
The research can be found in Frontiers in Ecology and the Environment.