Find a Fish
Numbfish Hypnos monopterygium
Follow-up letter on feeding
Dear Mark,
Whilst browsing the net I came across an inquiry sent to you of a Numb Ray found with a rat in its stomach. Whilst I too am very skeptical as to how the rat would have been taken by the ray, I must point out that despite their small mouths, Numb Rays are able to take incredibly large prey. Most literature states that Numb Rays prey on worms and crustaceans, however in my experience of their captive management I have found that they will only take fish.
As Unit Supervisor of Taronga Zoo Aquarium until its closure in 1992 I undertook a captive management study of Hypnos monopterygium as the Aquarium had never previously been successful in keeping them in captivity. We found that the rays would only feed on fish (only whole fish initially) that were presented to them on a plastic stick which was 'swum' past their nose. They rays required a soft substrate such as sand or fine shellgrit to bury into. Their attack of the prey was incredibly fast, without any warning, and was always accompanied by an electrical discharge. The prey item (including very large fish) would be swallowed head first, whole, very quickly before the animal would re-bury itself.
Therefore, whilst I am unsure as to how it came across the rat, I am confident that it would of been able to swallow it. I am very keen to pursue further work on Numb Rays and produce a paper or two on some of our findings.
Regards,
Craig Henderson
View the Numbfish fact sheet.
Letter from S. McMahon on Numbfish that had eaten penguins.
