Snowflake morays, Echidna nebulosa, exhibit similar feeding kinematics in terrestrial and aquatic treatments

Abstract

Some species of durophagous moray eels (Muraenidae) have been documented emerging from the marine environment to capture intertidal crabs but how they consume prey out of water is unknown. Here, we trained snowflake morays, Echidna nebulosa, to undulate out of the aquatic environment to feed on land. On land, snowflake morays remove prey from the substrate by biting and swallow prey using pharyngeal jaw enabled transport. Although snowflake morays exhibit smaller jaw rotation angles on land when apprehending their prey, transport kinematics involving dorsoventral flexion of the head to protract the pharyngeal jaws and overall feeding times did not differ between terrestrial and aquatic treatments. We suggest that their elongate body plan, ability to rotate their heads in the dorsoventral and lateral directions, and extreme pharyngeal movements all contribute to the ability of durophagous morays to feed in the terrestrial environment.

Keywords: Elongate body plan; Muraenidae; Pharyngeal transport.

Fig. 1.

Box plots showing the effects of treatment (terrestrial/aquatic) on each of the four kinematic variables. (A) Average jaw rotation angle, (B) average dorsoventral flexion, (C) average number of protraction–retraction cycles, and (D) log-transformed average total feeding time. Average jaw rotation angle was the only kinematic variable that significantly differed between treatments (*P=0.014).

Fig. 2.

Representative images of a snowflake moray feeding on the ramp in the terrestrial treatment. (A) The moray rotates its head laterally to bite the prey after attempts to bite the prey by dorsoventral flexion of the head were not successful. (B) The moray uses dorsoventral flexion of the skull, marking the beginning of prey transport.