Reference for Chullin 252:46

ומאן דמתני לה אסיפא אבל רישא אע"ג דלא השריץ

Our Rabbis taught: Since Scripture mentioned 'the mouse'<span class="x" onmousemove="('comment',' Lev. XI, 29: And these are they which are unclean to you among the creeping things that creep upon the earth: the weasel, and the mouse, and the toad after its kind.');">²¹</span>

Jastrow