An animal's biological category under Islamic dietary law is only half the question; how it is killed is treated as equally decisive, so that an otherwise permitted animal, a sheep or a chicken, becomes forbidden if slaughtered incorrectly, while the manner-of-death prohibitions stated outright by the Quran, carrion, animals that died of strangling or a fall or a wild beast's attack, are really a single principle stated several ways, that flesh from an animal not properly and intentionally slaughtered by a human hand invoking God's name is not permitted regardless of the species involved.
The method required, dhabiha, a swift cut to the throat severing the windpipe, oesophagus and the major blood vessels while pronouncing God's name, is understood across the major schools as serving both a stated religious purpose, dedicating the act to God rather than to any other power, and a practical one widely discussed in later commentary, draining blood from the carcass, since the Quran separately and repeatedly forbids the consumption of blood itself alongside the named forbidden meats. This tying together of species, cause of death and manner of slaughter into a single integrated system, rather than treating them as three separate rules, is part of why the halal and haram framework, like the parallel biblical system it is often compared to by scholars of comparative religious law, resists being reduced to a simple list of forbidden species and instead functions as a comprehensive framework governing the entire act of obtaining and preparing meat.