animal Type
Maximum Size

30 cm

(12 inches)


200–1,500 m

(660–4,900 feet)



in the twilight (mesopelagic) and midnight (bathypelagic) zones


Invertebrates and fishes

including crustaceans, arrow worms, and small fishes


Northern Pacific Ocean

Japan to the Bering Sea and Alaska, to Baja California and the Gulf of California


A big mouth isn’t an issue for this toothy predator.

Sleek, silvery, and adorned with modest bioluminescence along their bellies, Pacific viperfish (Chauliodus macouni) make fearsome predators for small fish and shrimp. They are among the countless marine animals that migrate each night from the ocean’s depths towards shallower surface waters to dine.

The Pacific viperfish’s needle-like teeth are the key to their hunting strategy. The two front fangs, which jut up from the fish’s bottom jaw past its own eyes, are especially dramatic. When viperfish unhinge their jaws, their mouths can open wide enough to engulf prey, while the teeth form a cage to prevent an escape.



Video Clips


Choy, C.A., S.H.D. Haddock, and B.H. Robison. 2017. Deep pelagic food web structure as revealed by in situ feeding observations. Proc Biol Sci, 284: 1–10.

Davis, A.L., K.N. Thomas, F.E. Goetz, B.H. Robison, S. Johnsen, and K.J. Osborn. 2020. Ultra-black camouflage in deep-sea fishes. Current Biology, 30: 3470–3476.