Furloughs have prevented staff from holding meetings on proposals to undo Obama-era environmental protections.
The former Montana congressman and Navy SEAL has faced plenty of questions about his air travel as secretary of the interior.
An Obama-era policy had banned the importation of endangered animals.
Ranchers and tribal leaders alike are taking a stand against Secretary Zinke's rollbacks.
The heads of the Interior and the EPA have defend Trump's plans to cut budgets.
The department manages about a fifth of the country's surface, including national parks, forests and tribal territories, from the Arctic to the Gulf of Mexico.
The Interior Department oversees territories covering a fifth of the United States' surface from the Arctic to the Gulf of Mexico, including sensitive wildlife habitats, iconic landscapes, rich deposits of oil, gas and coal and important pasturelands for ranchers.
A congressman and former Navy Seal, Zinke may be Trump's most interesting and unpredictable Cabinet choice.