Food too big...why knot?!

 

Over the last year, I have had the coolest independent research project at the University of California, Santa Cruz (UCSC). I watch California morays feed in a laboratory setting. Imagine that you are a large elongate predator that eats big but has no hands with which to manipulate your prey? What would you do in order to get prey into your mouth? Moray eels have evolved some amazing prey handling behaviors that involve their long bodies: rotational feeding, knotting, and ramming.

California morays are known as apex predator on temperate rocky reefs, consuming a variety of prey items (more to come on this topic in the next Lab Notes). We were curious as to how morays ripped off octopus tentacles, so a live two-spot octopus was offered to one of the eels housed at the Long Marine Lab at UCSC. Warning: Don't read on if you are skittish or have a vivid imagination.

Our moray, Scout, used one of its more impressive behaviors which we term "death rolling." During a death roll an eel rotates along its longitudinal axis, reaching up to 10 rotations per second! When Scout was finished death rolling, it began knotting the stunned octopus prey. During knotting, Scout formed loops in a figure eight fashion starting from its tail and tightening up toward its head. Knotting can break off pieces of prey, but also assists in transforming large prey items into more manageable pieces to swallow. In order to transport and swallow large prey, moray eels, in general, have high specialized, mobile pharyngeal jaws. Once the moray has a prey item locked between its oral jaws, these pharyngeal jaws protract from the back of their throat grabbing, and retracting the prey back into their esophagus. How is that for doing damage to your prey without any hands!

Here's the knotting phenomenon in real time (the previous was 1/2 speed):

 

While I get to document all these exciting behaviors, my research project examines the effects of prey type (squid and fish) and size on the prey handling behaviors of morays. I have a complete data set for both prey species and recently presented my results at a national conference in West Palm Beach Florida. My experience in the Mehta Lab has helped me solidify my passion for behavioral ecology and I plan to apply to graduate school when I graduate from UCSC. -AD