Reference for Chullin 106:21

ולשהינהו שנים עשר חודש

Said R'Ashi: We hold, do we not, that wherever there is a doubt whether the animal was clawed by a dog or by a cat it may be assumed that it was clawed by a dog?

Jastrow

Jastrow

Jastrow

Jastrow

Jastrow

Jastrow

Jastrow