From Muppet Wiki

Jeremiah Tortoise is an elderly character introduced in the third season of Bear in the Big Blue House. The old tortoise works in the Woodland Valley Post Office. Jeremiah is also the sole proprietor of the Woodland Valley General Store. Avuncular but slightly absent-minded, Jeremiah recalls the days when Bear was attending high school. The tortoise is friends with Doc Hogg, and is the great-grandson of Woodland Valley founder Hephaestus Tortoise.

Jermeiah is the judge for the Annual Woodland Valley Storytelling Festival. Regarding his age, Jeremiah quips that he is old enough to not remember how old he is.

The puppet was also used as one of the pet shop animals in Kermit's Swamp Years, sans hair and goatee.