Rank 8: Meteor Strike
The Pokémon in this rank, just like Kabutops, cannot be blamed for going extinct. Chance did not deal kindly with the prehistoric Pokémon Aerodactyl (Gen 1). Though it is not directly confirmed in the Pokédex, the pocket monster lived at the same time as the dinosaurs. And everyone should know how they went extinct.
It is known that real animals once existed in the Pokémon world. Monargoras also likely had spectacular battles with other dinosaurs 100 million years ago. No one could stand against it – except for a gigantic chunk that fell from the sky.
Rank 7: Geographical Isolation
Armaldo and Wielie both come from the 3rd Pokémon generation. In episode 376 of the anime, their origin is explored in detail. It also becomes clear why the two Pokémon went extinct: due to geographical isolation. Presumably, the two prehistoric creatures could no longer catch prey.
With Wielie, it is additionally stated that it was, like the Pokémon in rank 10, too slow. Even on the ocean floor, it had to drag its body. During low tide, Wielie would go to the sand to hunt for prey. Due to its too short legs, it likely moved even slower on land.
Rank 6: Incomplete Protection
Bollterus (Gen 4) has a tough head – in the literal sense of the word. The shield Pokémon has a shield as a head and can fend off its enemies with it. When several Bollterus are in a herd, they position themselves all around to protect their young.
But what if a single Bollterus is out alone? Here, evolution did not think fully ahead, because from behind the Pokémon is defenseless. Presumably, Bollterus relied too much on its front before it became extinct.
More causes of death can be found on page 3.
