Ancient shark-eating whale

[Startraveler]

Pretty cool.

Nature:

Ancient whale 'truly weird'

Blue whale's aged cousin: small, enormous eyes, ate sharks.

Richard Van Noorden

A 25-million-year-old whale fossil from southeastern Australia has revealed a bizarre early type of 'baleen' whale. The creature was an ancient cousin of our modern blue whales and humpbacks, but it was hardly a gentle giant of the sea. Instead it was small and predatory, with enormous eyes and teeth.

Enormous blue whales and humpbacks fall into the category of baleen whales (Mysticeti), which have no teeth, feeding instead by filtering out krill and plankton from huge gulps of sea water. For filters, the whales use large whalebone or 'baleen' plates arranged in comb-like rows on their jaws. Blue whales can grow up to 30 metres in length.

But the fossil relative of these whales, Janjucetus hunderi, discovered in Jan Juc, Victoria, looks quite different. "It's almost like a whale from outer space: truly weird," says study author Erich Fitzgerald of Monash University in Clayton, Australia. "In overall appearance and lifestyle, it looks more like a modern leopard seal." The skull is just 50 centimetres long, meaning that the whale would be no larger than a bottle-nosed dolphin. The snout is foreshortened, quite unlike the surfboard-like elongated snouts of modern whales, which have adapted to increase their surface area for filter feeding. And the eye sockets are enormous relative to the whale's size.

Furthermore, Janjucetus has large sharp teeth but no baleen. Considering its shape and large eyes (providing good underwater vision), it looks as though this whale was a predator that ate large fish — possibly sharks and other whales, Fitzgerald speculates.

Toothless, but toothed?

How, in that case, does Janjucetus count as a baleen whale? According to Fitzgerald, there are specialized features in the fossil whale's anatomy - where the snout meets the brain case, and at the base of the skull near the ear region — that are unique to baleen whales. And Janjucetus can't echolocate, a defining feature of modern toothed whales, such as sperm whales and dolphins.

The fossil was discovered by a teenager in the late 1990s, and fortunately was stored in Museum Victoria, Melbourne. There it languished, unstudied, until Fitzgerald found out about it in 2003. It took another three years to remove the fossil from the mudstone that encased it.

Janjucetus throws new light on the evolution of baleen whales. Such whales were already known to have originated from toothed whales; modern baleen whales go through a stage as embryos in which they have teeth. But there is a blank period in the fossil record between ancient toothed whales that lived 34 million years ago, and a profusion of various lineages of whale and dolphin — including baleen whales — that came into being around 25 million years ago.

It had been assumed that when this explosion of whale specialization happened, baleen whales all took the path of toothless filter feeders. The fact that this toothed whale lived alongside them contradicts this idea.

But the concept of a toothed baleen whale didn't really catch on. This species was in an evolutionary cul-de-sac that subsequently died out, whereas the sharks it may have fed upon have survived to the modern day.

[Conspiracy]

and at other places in that same time giant sharks ate modern sized whales

[The Carnivore]

and at other places in that same time giant sharks ate modern sized whales

Ironic, aint it?

[Poetic Reven]

Weird..... Very weird.

[rapid7]

In the BBC documentary 'Walking with Beasts' the follow up to Walking with Dinosaurs, they covered this whale in one episode.

Quite impressive graphical reconstruction of the carnivorous whale.

[Jok3r]

Very interesting. There's not picture of this whale? Besides the drawing.

Edited August 17, 2006 by MindFreak718

[rapid7]

My mistake, I thought it was about Basilosaurus

Basilosaurus with a skull as long as a sofa and a total body length equivalent to that of three elephants, this early whale was at the top of the underwater food chain. To maintain its incredible weight — it was as heavy as two tanks — Basilosaurus was an eating machine that could swallow sharks whole. Fossils also show a reminder of its land-animal ancestors: a pair of tiny back legs.

Edited August 17, 2006 by rapid7

[frogfish]

Some articles call this whale "Aussie's T-rex of the Ocean"...Should I remind them the more formidable Kronosaurus swam the wtaters...

[The Carnivore]

Some articles call this whale "Aussie's T-rex of the Ocean"...Should I remind them the more formidable Kronosaurus swam the wtaters...

aye, and not to mention Liopleurodon.

[frogfish]

Liopleurodon live in the waters where Europe currently is. Not in Australia.

Edited August 21, 2006 by frogfish

[draconic chronicler]

Yes frogfish, but the point is, the great sea reptiles were dead for millions of years when basilosaurus ruled the waves. Krono had a much bigger head and jaws, but basilo may have had warm-blooded advantages that made it a more effective predator.

[BigDaddy_GFS]

Here's something I found.

Source

[Troll Account]

What a fearsome animal,I wonder if they hunted in packs (herds? schools? what's the word for group of whales?)

[Never_Hit_Nirvana]

What a fearsome animal,I wonder if they hunted in packs (herds? schools? what's the word for group of whales?)

Pods.

[frogfish]

Predatory sea animals are normally solitary...The only whales that go on group hunts are orcas.

[Mystilily]

Actually there are a few whales that group hunt and feed.

Beluga whales form pods and are known to hunt together.

Sperm Whales as well have been observed hunting in smaller pods. In 1998, off the coast of Indonesia, 3 sperm whales were observed attacking a megamouth shark.

Bottlenose dolphins, though not a true whale are known to hunt in pods.

Narwhals form in pods and feed together. They have even been observed grouping with belugas for hunting/feeding times.

As mentioned, the orca or killer whale is of course the best documented and best known pod hunters.

While not a toothed whale, Humpbacks do bubble net feeding which is a group hunting activity.

Bowheads form up pods in the fall of up to 50 whales, during which time they hunt and feed.

Byrde's whales form loose groups during feeding times.

Grey whales are known for pod forming and feeding.

Minke whales form groups on feeding grounds.

While some of these listed are not toothed whales or viewed as predatory creatures. Examination of the habits of feeding of the entire spectrum of species might show a valuable clue to if they could or would have used such method. I think it's highly possible they did use a group method of feeding much like our modern whales do now