Several trees native to North America and South America once produced huge fruits and relied on large mammals (giant sloths, tooth worms and so on). ) to eat fruits and spread seeds. Since these animals are now extinct, human beings are now the only way for seeds to spread and grow into new plants.

Of course, you might say that since hunting by prehistoric humans was the cause of the extinction of these large mammals, if humans didn't exist at all, these trees might still be alive. But today, humans are the only reason why they are not extinct. )

Here are some examples:

Mulberry orange (Maclura pomifera) is a large and lumpy fruit, which may be the food of mammoths at first. Mammoths use their huge molars to pry open hard fruits and seed coats, and seeds can germinate. This kind of fruit is non-toxic, but it is hard, and it has no teeth as big as those of existing North American animals to grind it, so it will fall to the ground and remain motionless. After the extinction of mammoths, Oz Orange only appeared in the Red River area of Texas. The red river will send a lot of water, and the flood will hit the fruits on the rocks, causing them to crack and the seeds will germinate.

In the 1930s in the United States, when sandstorms blew away all the soil, the agricultural areas in the midwest were in trouble. Later, it was found that the mulberry trees planted around the farm grew fast and could keep out the wind, so under President Roosevelt's "Great Plains Shelterbelt" plan, human beings planted mulberry trees all over the United States. They still can't grow from seeds by themselves, but humans grow them in large quantities.

(Source: Wikipedia user katputaka)

Avocados are another plant that provides fruit for an extinct animal, which may be a giant ground sloth. Their seeds (slightly toxic) will pass through the sloth's digestive system and eventually enter the sloth's feces to become the sloth's fertilizer.

Humans seem to have discovered a long time ago that if you pick a lot of avocados and store them in closed containers (such as baskets), they will release a chemical to make them softer and edible. Then humans planted it everywhere. Because they are delicious.

Avocados are not completely dependent on humans like mulberry oranges-if an avocado falls from a tree, the fruit will rot and the seeds will eventually sprout under the mother tree. But without human help, they can't move to any new area (or like oranges, floods can transfer big seeds), so without human beings, they will gradually become extinct.

(Source: Wikipedia B.navaz)

Kentucky coffee tree (Gymnocladus dioicus) also provides fruit for mammoths. Its pods are hard and tough, and no one can eat them except mammoths or people with knives.

After the extinction of mammoths, coffee trees only survived in some small swamps. Acidic swamp water can dissolve tough seed pods and make seeds germinate. In fact, it doesn't like to grow in swamps. It grows better in a wet but not underwater environment. But the swamp is the only place where seeds can grow without the help of mammoths.

Archaeologists found the grove of coffee trees in the ruins of native American villages, so we know that Native Americans probably stopped the extinction of coffee trees by cutting coffee beans and planting seeds around their villages. They roasted the seeds and ate them. I haven't tasted it, but it is said that it tastes like coffee, so it has this name.

Coffee trees are sometimes planted in cities and parks because they look cool and strange, but they are very rare species at present if they are not planted by Native Americans.