Definition of hagfish in US English:



  • A primitive jawless marine vertebrate distantly related to the lampreys, with a slimy eel-like body, a mouth surrounded by barbels, and a rasping tongue used for feeding on dead or dying fish.

    Class Myxini and family Myxinidae: several genera, in particular Myxine, and numerous species

    • ‘Hermaphrodites were rarely observed in a study on the Japanese hagfish.’
    • ‘All early fishes - and two modern survivors of this initial radiation, the lampreys and the hagfishes - lacked jaws.’
    • ‘In contrast, the vertebrate insulin gene became a metabolic regulatory action of insulin early during vertebrate evolution since insulin regulates glucose homeostasis even in hagfishes and lampreys.’
    • ‘They are represented now only by the lampreys, eel-like forms that are parasites on fish, and the hagfish, also eel-like but feeding on dead or dying animals.’
    • ‘One form is lamprey like, whereas the other is closer to the more primitive hagfish.’
    • ‘This jawless mouth sets the lamprey and its cousin the hagfish apart from all other modern vertebrates - animals with backbones.’
    • ‘It used to be thought that hagfish were vertebrates, but in fact these ‘fish’ have no backbone at all.’
    • ‘For a long time, people thought of hagfish as scavengers and parasites, probably due to their habit or burrowing into dead or dying animals and eating them from the inside out. In’
    • ‘The hagfish, together with lampreys, are living representatives of the jawless vertebrates (class Agnatha) and are considered to be the most evolutionarily ancient vertebrates.’
    • ‘Agnathans generally have the smallest brains for their body size, with hagfishes having brains that are two to three times larger than lampreys of the same body size.’
    • ‘Apparently living at great depths with the hagfish, the prehistoric ratfish was recently discovered off Brazil by scientists.’
    • ‘To date, the question of luteal-like structures in lampreys and hagfish is unresolved.’
    • ‘Hagfish live in burrows on the seafloor and locate their food by smelling and feeling as they swim.’
    • ‘Whatever their phylogenetic position, the hagfish are still considered the most primitive vertebrate known, living or extinct.’
    • ‘Traditional methods of population assessment used by the fisheries industry cannot be applied to the hagfish.’
    • ‘In addition, there is little known about how the hagfish feed, grow, or sexually mature.’
    • ‘It has been suggested the demand for hagfish skin has greatly depleted the hagfish populations.’
    • ‘These data from our studies suggest a seasonal reproductive cycle in the Atlantic hagfish.’
    • ‘The absence of a cerebellum in hagfishes and lampreys appears to be the only exception.’
    • ‘These first vertebrates lacked jaws, like the living hagfish and lampreys.’


Early 17th century: from hag + fish.