for various kinds of work(B.M. 86b; Hag. 3b; Meila 13a; A.Z. 5b, etc.). Consumption or sacrifice was limited to those deemed clean(Lev. 11:3ff); the list included animals, birds, and fish. Other animals that were unclean could be used by humans in various ways. There were few limits on the manner of catching or housing animals as long as it was humane, so a varieties of means of catching birds were discussed in the Talmud (B. M. 42a; Taanit 22a; Shab. 78b; Ber. 9b; etc.). Animals that endangered human beings, such as wolves and lions, could be destroyed(Ber. 13a). This was even more true of pestilent creatures such as grasshoppers, mosquitoes, scorpions and ants. Crop eating field mice and rats could also be destroyed(Taanit 14a, 19a; Shab. 121b; M.K. 6b). The Midrash that sought to find a use for animals such as fleas and mosquitoes stated that they were created in order to plague evil people(Midrash Rabbah Vayikra 189).
Animals could be used by humans as long as they were treated kindly. It is prohibited to consume a limb from a living animal(B.M. 32b). An animal that was threshing may not be muzzled; it must be permitted to eat as freely as a human being (Deut. 23:25f.; B.M. 87b, 90a; Yad, Hil. Zekirut 13.3; Shulhan Arukh, Hoshen Mishpat 338). Furthermore, one should not consider acquiring an animal unless one has the means to feed it(J.T. Ket. 4.8), and a person should then feed his animals before feeding himself(Git . 62a; Yad, Hil. Avadim 9.8).
Unnecessary pain may not be inflicted on animals(Ex. 23:5; B.M. 32a; Yad, Hil. Rotzeah 13.9; Solomon ben Aderet , Responsa 252, 257). Some of the medieval scholars who were concerned with the protection of animals felt that those precautions needed to be stricter than those for human beings, as animals do not have the intelligence to care for themselves or to take a longer view of matters(Yad, Hil. Zekhirut 13:2; David ibn Zimri, Responsa I 728; Yair Hayim Bacharach, Havat Yair 191; Shulhan Arukh, Hoshen Mishpat 337:2). Biblical law prohibited the killing of a mother with its young(Lev. 12.28; Hul. 83a; Yad Hil. Shehitah 13; Shulhan Arukh, Yoreh Deah 16). The later Jewish codes also insisted that a seller inform a buyer of the relationship between any animals sold so that a mother and its offspring would not be slaughtered together on the same day. A similar kind of provision forbade the taking of both a mother and a chick from the same nest(Deut. 12:6; Hul. 138b Shulhan Arukh, Yoreh Deah 292).