Congress passed the Animal Welfare Act 1 (AWA) in order "to ensure the humane care and treatment of various animals used in research or for exhibition or kept as pets. 2 To this end, the Act requires, inter alia, that the Secretary of Agriculture 'promulgate standards to govern the humane handling, care, treatment, and transportation of animals by dealers, research facilities, and exhibitors. "' 3 The Animal and Plant Health Inspection Service (APHIS), the agency under the U.S. Department of Agriculture responsible for implementing the AWA, first promulgated regulations pertaining to the care of marine mammals in captivity 4 in 1979 and has updated various aspects of these regulations on a limited basis since then. The last time the marine mammal care regulations relating to the physical conditions under which these species are held were substantively revised was in 1984. 5 On 3 February 2016, APHIS published a proposed rule to amend the captive marine mammal regulations. 6 The agency took 14 years to issue this proposed rule 7 and had it under consideration for 20 years. 8 APHIS's marine mammal care regulations are intended to "insure that animals intended … for exhibition purposes … are provided humane care and treatment. " 9 The statute does not, however, define the term "humane. " In the absence of a statutory definition, it is appropriate to "look to the common usage of words for