Nocturnal. Occur in offshore waters, mostly captured by dredging at 10 m or deeper. Occasionally caught at surface. Are often camouflaged within the branches of gorgonians and black coral trees where they are seen to curl their tail around the branches (Ref. 5227). Have been found in the stomachs of Pacific yellowfin tuna and bluefin tuna (Ref. 30915). Ovoviviparous (Ref. 205). The male carries the eggs in a brood pouch which is found under the tail (Ref. 205).