Mammothmon

Mammothmon is an Ancient Animal Digimon whose names and design are derived from the woolly mammoth (Mammuthus primigenius). The fact that this ancient Digimon existed long ago was made clear from a multitude of evidence. Due to Digital World warming, its super-compressed data was expanded, and it made its way from the once-icebound Ice-Snow Area. Its whole body is covered in dense fur, and although it is an ancient Digimon that possesses immense power, it also has a weakness to extreme heat. The crest engraved into the mask covering its face is a super-ancient crystal of wisdom, so it possesses the power of clairvoyance so that it is able to see far into the distance, and its large ears can even identify sounds from faraway places.

LOTM: Dynasty Warriors
Some of the Mammothmons were living in the time of Ice Age, along with Mamoswine. Suddenly, Mammothmon population got decreased. All of the Mammothmons became extinct, thus marking the end of Ice Age.