Inhabit deep waters (Ref. 4570). Epibenthic-pelagic (Ref. 58426). Bear live young. Gregarious throughout life. Feed on euphausiids, hyperiids, cephalopods, chaetognaths and small fishes. Ovoviviparous (Ref. 4570). Longevity was determined from isotope ratios and given as at least 65 years in general and at least 75 years in the waters off Nova Scotia (Ref. 45673).