Its impressive tusks are made of ice. The population thinned when it turned warm after the ice age.
A frozen one was dug up from soil dating back 10,000 years. It woke up to much amazement.
A frozen MAMOSWINE was dug from ice dating back 10,000 years. This Pokémon has been around a long, long, long time.
It flourished worldwide during the ice age but its population declined when the masses of ice began to dwindle.
When the temperature rose at the end of the ice age, most Mamoswine disappeared.
— Pokédex entries (via PokeAPI)