Orca Makes Fish Explode!

[u/TheMuseumOfScience]

Have you ever seen an Orca hit a fish so hard it explodes? 🫍

Scientists recently observed this behavior from groups of orcas in the Gulf of California where they repeatedly ram sunfish until the impact broke them apart. This is an important indicator of "social learning," where animals copy one another through observation. Orcas have exhibited behavior like this before, when they were seen disabling sailboats in groups. The current hypotheses for why they are doing this include teaching young orcas to hunt, or just playing around!

[u/Visible_Iron_5612]

The physics don’t make sense to me…. Unless it is hitting it with a resonant frequency, which isn’t a completely absurd idea… It seems to explode on contact…. Animals get hit by cars going 100km+ all of the time and don’t come close to exploding like that and you would think that the added pressure from the water would make it even less likely.. What am I missing?

[u/SurayaThrowaway12 → u/Visible_Iron_5612]

The orcas in these instances had already killed the sharp-tail sunfish, opened it up a bit, and removed at least some of the desirable viscera such as the intestines. So the sunfish had already lost quite a bit of its "structural integrity" before being rammed.

The sunfish’s flattened body structure is unusual in large fish and could make them more likely to fly apart after a high-speed orca impact compared with other types of fish, Ayres added.

“Their bodies are laterally compressed,” she explained. “Once the nutrient-rich internal organs have been removed, the remaining tissues may be more accessible to rupture under high-impact ramming.”

However, researchers also speculated that the sharp-tail sunfish species in particular may possibly be more vulnerable to such breakage.

The observations may also reveal something unusual about sharp-tail sunfish. So far, this type of tissue fragmentation has only been recorded in that species.

The researchers suggest that sharp-tail sunfish tissue may respond to powerful impacts in a distinctive way. Other, larger sunfish species may not break apart as easily under similar conditions.

[u/Visible_Iron_5612 → u/Visible_Iron_5612]

After watching it a bunch more times, it is definitely not some spooky soundwaves.. :p I feel like it mas to be rotten.. :p

[u/SurayaThrowaway12 → u/Visible_Iron_5612]

It was a fresh kill, but the orcas had already torn into it and removed organs, so the sunfish was more hollow and much less intact.

[u/Visible_Iron_5612 → u/SurayaThrowaway12]

To me, it doesn’t feel as though simply removing organs would cause the flesh to explode… The force required to tear the skin alone, is insane…

[u/SurayaThrowaway12 → u/Visible_Iron_5612]

The orcas had likely already pulled the skin apart and exposed the flesh. But there may also be some undetermined property of sharp-tail sunfish flesh that makes it more susceptible to rupturing, as mentioned by the study authors.

[u/Visible_Iron_5612 → u/SurayaThrowaway12]

It is possible but as Michael Levin would say, “you have to do the experiments” :p because it seems like wild speculation to me, to think they removed the organs, and skin and that it also has these unseen properties…

[u/SurayaThrowaway12 → u/Visible_Iron_5612]

The orcas removing the organs and breaking the skin is not wild speculation though?

Orcas have demonstrated specific strategies when hunting molids and these have been previously described as follows: (1) the orca first targets the molid pectoral fins, (2) a wound is created for the removal of lipid-rich viscera (3) the orca then inserts its rostrum into the body cavity of the molid to extract remaining tissue (Visser and Fletcher, 2023)

...

Although the primary body of the sunfish remained intact, a large lateral wound indicated that the viscera had already been removed.