Urging FWS Not to Rescind Regulatory Definition of ‘Harm’ Under the Endangered Species Act

On May 19, 2025, the Animal Legal Defense Fund (ALDF) and the People for the Ethical Treatment of Animals (PETA) submitted comments to the U.S. Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS) urging them not to rescind the regulatory definition of “harm” under the Endangered Species Act (ESA) in the agencies’ proposed rule. The ESA prohibits the “take” of endangered or threatened animals, and “harm” is one element of the definition of “take.” 

The proposed definition of “harm” from FWS and NMFS asserts that “take” simply means to “kill or capture a wild animal” and that the current regulatory definition of “harm” expands the reach of “take” too far to “prohibit actions that impair the habitat of protected species.” However, as ALDF and PETA explained in their comments, the currently existing definition is not improper because Congress intended the ESA, and its prohibition on “take” in particular, to be read broadly to ensure the protection of endangered animals who could be impacted by the degradation of their natural habitats.

The ESA has been recognized as the “most comprehensive legislation for the preservation of endangered species ever enacted by any nation.” When enacting the ESA, Congress intended to “halt and reverse the trend towards species extinction, whatever the cost.” The ESA’s stated purpose is to “provide a means whereby the ecosystems upon which endangered species and threatened species depend may be conserved.” The declared policy of Congress is that “all Federal departments and agencies shall seek to conserve endangered species and threatened species and shall utilize their authorities in furtherance of the purposes” of the ESA. As ALDF and PETA explained in their comments, the FWS and NMFS achieved Congress’s intended purpose of protecting listed species and their habitats by defining “harm” to include habitat modification or degradation leading to actual injury or death.

If the FWS and NMFS rescind the “harm” definition, the comments argued, the intent of the law will remain unchanged. The comments cite Babbit v. Sweet Home Chapter of Communities for a Greater Oregon to describe how the Supreme Court majority went beyond merely upholding one permissible interpretation of “harm,” and instead conducted a thorough, independent statutory analysis that concluded “harm” and “take” were meant to be read broadly. As a result, the FWS and NMFS current regulatory definition of “harm” is the best meaning of the term, which should remain guiding even if there is no written definition in the regulatory books.

What action has been taken? ALDF submitted comments to the FWS and NMFS urging the agencies not to rescind the regulatory definition of “harm” under the ESA in the agencies’ proposed rule, while also arguing that such an action would not alter the current meaning of the term as it relates to habitat modification.

Why this proposed rule is important: Congress provided FWS and NMFS the authority to implement and enforce the ESA. The FWS and NMFS promulgated regulations defining “harm” to clarify that actions that significantly modify or degrade a listed species’ environment that actually kills or injures a member of a listed species constitutes a “take.” Congress intended for “take” to encapsulate a broad number of ways in which a person could “take” listed species. Without a broad reading of the definition of “harm” as Congress intended, endangered species will not be protected sufficiently as required under the ESA.