Beluga and narwhals are surprisingly tolerant with each other [1] but whales have "cultures". What mother eats is eaten by the offspring. A different diet points towards a captive animal. Hybrids in dolphins happen with relative ease in captivity. Maybe related with beluga experiments by Russian navy, maybe the former inhabitant of a zoo.
A captive whale is a very interesting theory. Could the different diet be the result of being fed by humans?
I found this[0] interesting story from April about a tame beluga that approached
a Norwegian fishing boat. It was wearing a tight harness, apparently meant for a camera, with markings that suggest a Russian origin.
I also found a very recent case where a Russian company illegally caught nearly 97 belugas and orcas and kept them in pens[1]. 8 of them were to be released today. This company supplies whales to aquariums.
Could be. Diet study in skulls is all about isotopes. Different isotopes mean different preys, or preys from different trophic chains that in practice mean different locations.
Would be interesting to know details about the death of the animal and how old and how was preserved the skull. If is a very old skull could mean also that the ecosystem in the same area has changed, and the whale feeded on preys that became rare later. Is well known that fisheries flourished in both world wars by the presence of submarines and frigates. Offshore fishing was a very dangerous activity in those years, so our common "war against fishes" stopped for a while.
I have to say the teeth are absolutely fascinating.
> The hybrid skull has a set of long, spiraling and pointed teeth, that are angled horizontally.
Narwhals do not not have teeth (beyond two vestigial ones behind their spiraled tusk). Belugas have 40, which are vertical. This cross-breed ended up with 18, spiraled, horizontal teeth. Which it seemingly adapted to raking the sea floor with.
Huh, narwhals and belugas aren't even in the same genus. Most well-known hybrids like tigers and lions, horses and donkeys, and tomatoes and potatoes have been between species in the same genus. Maybe this discovery will prompt biologists to place narwhals and belugas in the same genus? It must be lonely being the sole member of a genus, after all.
If I recall my high school biology correctly, the strict definition also has the requirement that the offspring are able to reproduce themselves (hence making donkeys and horses separate species).
The article mentions no evidence that in this case the hybrid was able to reproduce, since it's all based on the analysis of only one skull.
I'm not sure there is a strict definition of species. Take a ring species where A and B can interbreed and B and C can interbreed but A and C cannot. If some event kills all the B's, then you have two species instead of one. That you can make new species by killing only seems quite odd.
"Ring species" are a fascinating thing, they really turn out to be a litmus test for testing notions of speciation.
I think it turns out just that "species" is just a human construct. It's not something hard-and-fast that nature hews to. It's nothing but a construct we use for convenience in our drive for labels.
I think colors are a good analogy. Colors exist and are distinct at certain distances from each other, but things start to get blurry the closer two colors are to each other. For instance, is turquoise blue? Is it green? It's kinda both.
Same with organisms and populations. The farther away (evolutionarily speaking) two populations of interbreeding organisms are, the easier it is to distinguish them into different species. The closer they are, the more things start to look like turquoise.
Does cross-breeding ability automatically mandate a shared genus? Could they have genetically drifted in enough ways to be in separate genuses, even if reproductive compatibility isn't one of those ways?
One thing I’m curious about is how the researchers even tell that the hybrid is a bottom dweller. They have only seen the skull, not what was inside the hybrid’s stomach. Can some biologist shed some light here?
So I was still thinking about this question while taking a shower. Did the researchers come to that conclusion by analyzing food stuff that was still lodged in the jaws?
Oops, upon rereading, I just spotted “isotope analysis”. How different are isotopes between water-column diet and bottom diet?
This is super interesting: "We observed a general increase in sterol δ13C signatures with depth, which is likely related to a combination of particle size effects, selective feeding on larger cells by zooplankton, and growth rate related effects"
Carbon-14 is created in the atmosphere where it is C02 and photosynthetic organisms convert it to more complicated organic compounds. The rate of diffusion of the Carbon-14 through the water column is measurable.
With regard to horses and donkeys a "mule" is the offspring of a male donkey and female horse [1], while a "hinny" is the offspring of a female donkey and a male horse [2].
There was an article in The Atlantic with a bit more info, but the hunter that killed it initially called it a narluga. That stuck in spite of the convention being backwards: the genetics suggest the mother was a narwhal, which would make this particular combo a belwhal by the standard convention.
Meat in Cetacea is red, strong and similar to beef, but fish flavoured. Would be like eating a beef fried on fish oil. Sounds a little gross to me (but anything with a high fat content would taste delicious if you are in the arctic).
On the other hand, some Beluga meat is classified in the Toxic waste category so, probably not a good idea. They are prone to accumulate contamination byproducts and heavy metals in blubber
[1] https://www.youtube.com/watch?v=vJhGf7S4cSQ