If you were to move a desert animal to the tundra, it would likely struggle to adapt to the extreme cold temperatures and lack of familiar food sources. Desert animals are typically adapted to high temperatures, low humidity, and limited water sources, which are very different from the conditions found in the tundra. The animal may not have the necessary adaptations, such as thick fur or layers of fat, to survive in the cold tundra environment. Ultimately, the animal may not be able to find suitable shelter, food, or water, leading to a high risk of injury, starvation, or death.
What would happen to the animal is that it might die because throughout its whole life it lived in the rainforest. Also because it doesn't know how to live in a desert and it doesn't have the adaptions for the desert.
If anything, the plant or animal might live a bit better off as a grassland receives more rainfall than a desert. There are a number of plants and animals that already live in both the desert and the grasslands.
If a grassland animal moved to the Arctic tundra, you would be following a caribou on its annual migration. You would watch it graze on the grass of the tundra. Then when winter came, you would watch it move south to its winter grazing land. You might also be watching a musk ox which grazes on the tundra year around.An animal without a thick coat would of course freeze to death.
If the desert is located along a coastline it might be subject to a tsunami.
Animals move to other places or they will not survive. Or the population might grow.
Animals move to other places or they will not survive. Or the population might grow.
We may might not be on the same page, but I believe it is El Chupacabra
An animal might live in an underground habitat in a desert ecosystem to escape the extreme heat and dehydration at the surface. The underground burrows provide a cooler and more stable environment, protecting the animal from harsh desert conditions.
A desert animal may struggle to adapt to the high humidity and abundant rainfall of the rainforest. It could face challenges related to finding suitable food sources, navigating the dense vegetation, and avoiding predators it is not accustomed to. Without the specialized adaptations for the rainforest environment, the desert animal may have difficulty surviving.
you might be infected with rabies
Having traveled extensively in both deserts, I guarantee you will see a lot more fauna and flora in the Sonoran Desert. The Atacama Desert has little plant and animal life.
The Polar bears will die because they are used to living in a colder climate and not a warmer climat.