Yes, there are legal regulations for using humane wildlife traps, and these vary by country, state, or region. In the United States, the use of wildlife traps is regulated at both federal and state levels. The Federal Animal Welfare Act provides some guidelines, but most regulations are state-specific. States often have their own wildlife agencies that set rules on the types of traps that can be used, the species that can be trapped, and the methods for checking traps. 
For example, many states require that traps be checked within a certain timeframe, often 24 hours, to minimize animal suffering. Some states mandate the use of specific types of traps, such as cage traps, which are considered more humane than leg-hold traps. Additionally, the use of traps may be restricted during certain times of the year to protect breeding populations.
In the European Union, the use of traps is regulated under the European Council Regulation (EC) No 3254/91, which prohibits the use of leghold traps and restricts the import of pelts from countries that use such traps. Individual EU countries may have additional regulations.
In Canada, the Agreement on International Humane Trapping Standards (AIHTS) sets guidelines for humane trapping, which are implemented through provincial and territorial regulations. These standards focus on minimizing pain and distress for trapped animals.
Internationally, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) may also impact trapping regulations, especially for species that are threatened or endangered.
Overall, while regulations exist to promote humane trapping, compliance and enforcement can vary, and it is essential for trappers to be aware of and adhere to local laws and guidelines.