Many countries 'existing animal protection legislation and hunting laws aim to allow natural resources to be used sustainably by humanity, and are based on a spirit of compassion and humanitarianism. For instance, Japan requires anglers who catch fish fry less than a hand's length long to return them to the water.
許多國家現有與動物相關的保育法、狩獵法，為了讓自然資源能為人們永續利用，立法的出發點都頗富同情與人道精神，例如日本規定垂釣時，捕到體長不滿手掌的稚仔魚必須放回溪裡。