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The original title: "can sheep grow on trees and stones here?" The weak ask: can you eat it when cooked? "

(photo Source: Wikipedia) We often see sheep running and living freely on the prairie, shaking their fluff leisurely while eating grass. However, different from sheep, in another corner of the world, there is another kind of goat: they live on cliffs all their lives and are born to fly over the cliffs.

How do they develop a "light skill"? And what drove it to such a "dead end"?

I am afraid of heights. Wikipedia this goat is called snow sheep (scientific name: Oreamnos americanus). It mainly feeds on grass, ferns, moss and lichens that grow on high mountains. They live on steep slopes and cliffs above the tree line all the year round. As long as they have a foothold, no matter how steep they are, they can easily get up and down.

Of course, it's all thanks to the body structure of Snow Sheep that allows it to climb mountains: (1) their hooves have a hard shell that allows them to fit into gaps in the cliff wall that are almost invisible to the naked eye.

(2) the cushions at the bottom of their hooves are like hiking shoes. When exerting force, the cushions will firmly grasp the rugged surface of the mountain like a sucker and form a suitable shape.

(3) the toes are V-shaped and have a wide spacing, which can be flexibly separated and inserted into the cracks in the rock wall.

(4) Snow sheep have well-developed cantilevered hooves (that is, small hooves behind the main hoof), which can help them rest on the cliff and act as a brake.

(5) from the side, the snow sheep are thick and muscular, but from the front, they are narrow and long, and this body shape can help them keep balance on the narrow protrusions on the cliff.

Snow sheep's hooves | YouTube light observation of snow sheep's obvious structural evolutionary characteristics is far from enough, and people want to further understand their movement mechanism. However, because most of the snow sheep live in remote areas, the terrain is complex and inaccessible, it is difficult for scientists to observe the climbing process of snow sheep with their own eyes.

Biomechanics researchers Ryan T Lewinson and Darren J Stefanyshyn from the University of Calgary in Canada have come up with a simple (steal) easy (lazy) solution: watch videos on YouTube!

So they found a video of a male snow sheep climbing the Canadian Rockies on the video website and analyzed its movements frame by frame to see how the determined "climbers" managed to climb the near-vertical surfaces.

The picture shows 9 images of the climbing movement of the snow sheep, and the position of the center of gravity is represented by red hollow dots. The first 6 frames are the push-out stage of climbing, that is, the hind legs are in contact with the mountain surface, and the last 3 frames are the pull-up stage. | reference [2] Snow sheep climbing is mainly divided into two stages: push-off stage and pull-up stage. In the push-away stage, the front legs of the snow sheep are close to the torso, the hind legs stretch as far as possible, and the hillside surface gives a lot of thrust to the hind legs, and then draws the body by strong muscles attached to the neck and shoulders.

In the pull-up phase, Snow Sheep "locks" the forelimb humerus in a constant position relative to the torso, keeping the elbows close to the center of gravity of the body, and then raising the hind legs near the torso. at the same time, fold the front legs to keep the movement straight up.

Sheep: look at me flying along the eaves and walking down the wall! | YouTube researchers observed that the power point is actually in front of the shoulder of the snow sheep. This suggests that the neck muscles of snow sheep may provide additional muscle advantage during the climb. They also noticed that when climbing the mountain, the snow sheep seemed to be strategically bringing its front legs close to its center of gravity, making it easier for the hind legs to stretch to produce strong upward propulsion, rather than clumsily rotating its body.

A complete study on the climbing mechanism of goats was published on Zoology in the form of a paper A descriptive analysis of the climbing mechanics of a mountain goat. Of course, many people, including researchers, have a question about watching videos to study the climbing process of snow sheep: do all snow sheep climb in this way?

The researchers believe that this is a study of the opportunism of young snow sheep, and that snow sheep of other ages may climb rocks in different ways.

In other words, they also need to study something other than YouTube video.

There are many staggered sheep on the dam. [1] Why on earth do these sheep love cliffs so much? Scientists believe that the snow sheep climb the cliff to maintain the sodium needed by the body, lick off the salt and minerals from the rocks, and grow some plants because there are few other animals visiting the rock, so the sheep can eat food while replenishing salt.

David Saltz, a professor of conservation biology at Ben Gurion University in Israel, said: "Animal movement may be driven by more than one factor." In addition to the salt and minerals of stones, avoiding natural predators is also one of the reasons why they are keen on cliffs.

In the flat ground, the survival ability of snow sheep is not strong, in order to avoid the pursuit of beasts, they have no choice but to run to high places, and slowly develop the "flying eaves and walls" stunt. Although they have adapted so skillfully to cliffs, snow sheep fall from high altitude from time to time, and avalanches bury them. Snow sheep who survive are brave and lucky ones.

Goats flying trees have become a local wonder, and many tourists come here. Wikipedia Morocco has a similar herd of goats, except that their habitat has changed from cliffs to tree branches, with a slightly less thrilling degree. The goats, who like to climb trees, have repeatedly made headlines in recent years and were once considered a natural phenomenon unique to North African countries.

In fact, to some extent, it is still the survival instinct of sheep. We all know that the Sahara Desert in Morocco is dry and rainy. Although there are some grasses and shrubs, the quantity is limited and there is not enough food to satisfy the sheep.

And the tenacious Moroccan nut trees produce a ripe fruit that looks like withered olives around June every year, so under the pressure of survival, the goats here have evolved the ability to climb trees. take the leaves and fruits of Moroccan nut trees as their own food to ensure that they can survive.

Wikipedia Goats that climb trees not only save some food for the local residents, but also bring great wealth to the local people. Because after goats eat the fruit of a Moroccan nut tree, they leave a field of kernels under the tree, which can be squeezed into the world's most expensive cooking oil-Moroccan nut oil or a raw material for cosmetics. Moroccan nut oil can sell for $30,000 to $50 a liter.

Without the help of goats to eat nuts, it takes three days to grind a liter of Moroccan nut oil by hand, drying in the sun, separating the kernels, removing the kernels, leaving the nuts, and then carefully grinding them with a stone mill.

Nuts and kernels with a solid appearance | Wikipedia goats can walk flat between branches and cliffs no matter when they go up a tree or a cliff. From a distance, it looks like a cluster of goats growing on trees and rocks, so people have to sigh that they can see anything strange after living for a long time.

However, for sheep, the choice of cliff / fork or flat ground is a matter of life and death.

Cliff or flat? That's a question.

(image source Gifer) Resources:

[1] https://matadornetwork.com/life/32-photos-that-prove-goats-are-the-worlds-best-climbers/

[2] Lewinson, Ryan T.; Stefanyshyn, Darren J. (2016). A descriptive analysis of the climbing mechanics of a mountain goat (Oreamnos americanus). Zoology, (), S0944200616300514. Doi:10.1016/j.zool.2016.06.001

This article comes from the official Wechat account: take Science Home (ID:steamforkids), written by A Xian, revision: Skin

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