They are scavengers and many live at depths reaching thousands of meters.In addition, hagfish show the lowest metabolic rate as well as cardiac performance in vertebrates.

• 此特化的胸鳍是靠著两群肌肉控制伸展与收缩，这两群的肌肉外观均呈现淡红色，但未经组织学的证实，且两者生化特徵比较也尚无描述。