 Their pectoral fins are large and triangular, and extend straight out from the sides of their bodies like airplane wings.They have a venomous spine located at the leading edge of their dorsal fin, which is used in defense.It does not present a serious danger to humans, but can cause painful wounds and has been known to kill harbor seals that ate spotted ratfish (caused by the spine penetrating vital tissue in the stomach or esophagus after the ratfish was swallowed).