Goats in trees spitting seeds
It’s not unusual to see birds in trees. Pigeons in trees are a common sight in New York City. In Texas, noisy finches crowd trees along scenic roadways. In Washington, D.C., vultures loom high above the trees waiting for the opportunity to swoop down on unassuming middle-class citizens and their cherished tax breaks. But in south-western Morocco, hungry goats perch with acrobat-like agility high above the ground eating fruit and leaves and spitting out seeds. Goats? In trees? Spitting seeds? Dr. Suess, write this down, quick!
Goats in the boughs of trees are a common site in dry, arid areas like Spain and Mexico where edible ground-plants are harder for the goats to find. But the goats in trees in Morocco tower above all others. Locals say it’s common for 10-20 goats at a time to climb argan trees 20-40 feet high. Like a swarm of locusts, the goats devour the argan tree’s fruit and leaves, sometimes nearly stripping the trees bare.
The Argan tree and its yummy seeds
Argan is an important tree in the arid regions of Morocco. Argan seeds are used in beauty products and to make the most expensive edible oil in the world. Goats love the Argan tree’s pulpy fruit which looks like a giant, green olive. Herders in the area let the goats eat argan fruit and then collect the seeds they expel to refine into argan oil.
Scientists have long thought the goats excreted seeds as part of a mechanism called endozoochory where seeds pass through the entire intestine of the animal before being pooped out. But scientists recognized that some seeds, such as the seed from the argan plant, were too large for a goat to pass through the intestines.
Scientists grabbed their scoopers and headed to Morocco to ask local herders how the goats pooped out such large seeds. One herder wiped a glob of goo from his head, smiled at the silly scientists, and said, “They mostly spit out the seed from up in them trees over there”.
As skeptical scientists tend to do, they didn’t believe the lowly herders, so they took a bunch of hungry goats back to the lab and began feeding them everything from olives and hawthorn fruit to carob tree pods – five different kinds of seeds –of a variety of different sizes. They found that goats almost always spat out the larger seeds (those that were about the size of an acorn) and frequently spat out even the smaller seeds.
Reminiscing about ruminants
Ruminants are funny creatures. They acquire nutrients from food by fermenting it in a specialized stomach prior to digestion (yeah, it’s like a party in there). Animals that are ruminants include cattle, sheep, deer, and goats. Goat stomachs have four compartments. Food first travels to the rumen where the ingested food ferments. The goat then regurgitates “cud” from the compartment for a bit of extra chewing. Goats might chew the same food several times over a course of hours or even days. As a result, any seeds regurgitated can be spat out miles from where it was first swallowed.
Excretion vs. expectorate – a nasty business either way
Scientists found that nearly 75% of the seeds goats ate could still grow after being spat out. This is a much higher rate of success than seeds that have completely passed through the animal’s intestines before being pooped out. The tree-climbing goats of Morocco climb the argan trees, gather seeds in their stomachs, and help scatter the seeds of the plants they eat by spitting them out. Scientists now think all ruminant animals might accomplish the same task. Scattering seeds throughout the environment helps disperse plant life.
Do the goats ever fall from the trees?
Yes. Goats can’t fly. Not only do you have to watch for slimy seeds falling from trees, but you must watch for falling goats too. The herders told scientists it was not uncommon for the goats to fall from the trees, pick themselves up from the ground, wipe slime from grinning mouths, then clamber back up the tree for more tasty seeds.
More about how ruminants digest food
When a ruminant eats, food travels to the first chamber, called the rumen, where it mixes with saliva. The next chamber, the reticulum, separates solids and liquid. The solids are regurgitated as cud, and the ruminant chews it up some more. It is then swallowed again and passed on to the third chamber, the omasum. Here, water and inorganics are absorbed into the animal’s bloodstream. Finally, what’s left moves to the fourth chamber, the abomasum. The abomasum is basically the same as our stomachs and it digests everything that’s left.