Little Skate

Fascinating facts about the Little Skate

• Even though it looks like a flat fish, the little skate moves across the seafloor by "punting", pushing off with three-jointed leg-like pelvic fins called crura, then gliding on its wing-shaped pectoral disks; this gait mirrors land vertebrate walking and suggests the genetic basis for such locomotion may be 20 million years older than previously thought.
• Its tail hides a tiny electric organ that fires a 70 ms, head-negative monophasic pulse, likely used for communication and helping mates locate each other in the dim ocean depths.
• A typical adult measures 41–51 cm (16–20 in) long, but individuals in the northern part of its range can grow up to 54 cm (21 in).
• Females lay paired egg capsules no deeper than 27 m (89 ft); each case is 44–63 mm long and 30–45 mm wide, and in the wild the embryos may take up to a year to hatch, while captive eggs hatch in just 5–6 months.
• Little skates are used as model organisms in biomedical research alongside the spiny dogfish, with a BAC genomic library completed in January 2005.

At a glance

About the Little Skate

The little skate, Leucoraja erinaceus, glides over the soft sands and gravels of the northwestern Atlantic, its rounded disk spanning roughly one-and-a-half times its length and its blunt snout tipped like a tiny hedgehog. Its dorsal surface shimmers in shades of gray to brown, speckled with small dark spots, while the belly fades to a pale gray or white. Adults typically measure 41–51 cm, with northern individuals reaching up to 54 cm, and their sleek wings hide a suite of adaptations: a series of 38–66 round grinding teeth, strong spines on the head, shoulders and tail, and an electric organ in the tail that emits a brief, head-negative discharge lasting 70 ms, likely used for communication and mate location. By night these skates bury themselves near depressions carved by other creatures, emerging to hunt with a curious “punting” gait, propelling themselves with leg-like pelvic fin crura that push off the substrate and glide a short distance before resetting. This locomotion, reminiscent of early tetrapod movement, may reduce water turbulence, sharpening the skate’s electrosensory ampullae of Lorenzini for detecting buried prey. Their diet is dominated by decapod crustaceans and amphipods, supplemented by polychaete worms and occasional small fishes, reflecting a preference for epifaunal organisms atop the seabed. Reproduction is continuous, with females laying paired amber-to-greenish egg cases in shallow sand, each housing a single embryo that hatches after up to a year, emerging as miniature replicas of the adult.

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