MV Blog

DISPLAYING POSTS TAGGED: whale (3)

The biggest whale

Author
by Nicole K
Publish date
8 June 2012
Comments
Comments (0)

Your Question: Is the Whale Shark the biggest whale in the sea?

Whale Sharks are certainly big. The largest recorded was over 12 metres long!

A Whale Shark <i>Rhincodon typus</i> A Whale Shark Rhincodon typus
Image: Shiyam ElkCloner
Source: Shiyam ElkCloner, Wikimedia Commons
 

But Whale Sharks are not whales; they're sharks – the largest shark in the sea. Twelve-metre sharks might sound terrifying, but Whale Sharks are filter feeders. They eat plankton.

  A Whale Shark in the waters off Tofo Beach, Mozambique. A Whale Shark in the waters off Tofo Beach, Mozambique
Image: Jon Hanson
Source: Jon Hanson, Wikimedia Commons
 

The Whale Shark is not, however, the largest shark that ever lived. That was Carcharocles megalodon, popularly known as the Megalodon. Fossils indicate that this species grew to 16 metres long. Unlike the gentle Whale Shark, Megalodon was the stuff of nightmares. A formidable hunter, Megalodon had the largest teeth of any shark, immensely powerful jaws and enormous speed. Thankfully, Megalodon lived 28 to 1.5 million years ago.

The now extinct <i>Carcharodon megalodon</i> had the biggest teeth of any known shark species. Palaeontologists have found fossil Megalodon teeth that are 18cm long! The now extinct Carcharodon megalodon had the biggest teeth of any known shark species. Palaeontologists have found fossil Megalodon teeth that are 18cm long!
Image: Rodney Start
Source: Museum Victoria
 

The largest whale in the sea is the Blue Whale, Balaenoptera musculus. They are truly enormous. There is a complete skeleton of a Blue Whale on display at the Melbourne Museum. It's a whopping 17.2 metres long, but that's actually not that big in Blue Whale terms.

The Pygmy Blue Whale on display at the Melbourne Museum (<i>Balaenoptera musculus brevicauda</i>) The Pygmy Blue Whale on display at the Melbourne Museum (Balaenoptera musculus brevicauda)
Image: Rodney Start
Source: Museum Victoria
 

Melbourne Museum's Blue Whale is a Pygmy Blue Whale (the smallest of the three subspecies of Blue Whale) and it's not fully grown. It's only about half the length of the longest Blue Whale on record, which measured 33.58 metres! That is about as long as a Boeing 737 jet aeroplane. This not only makes Blue Whales the largest whales in the sea; it makes them the largest animal that ever lived!

The comparative sizes of a Blue Whale, a human and a Hector's Dolphin, the smallest cetacean (whales, dolphins and porpoises) The comparative sizes of a Blue Whale, a human and a Hector's Dolphin, the smallest cetacean (whales, dolphins and porpoises)
Image: T. Bjornstad
Source: T. Bjornstad, Wikimedia Commons
 

Sharks and whales are very different creatures. Sharks are fish; most are ectothermic ("cold-blooded") and breathe underwater through gills. Whales are mammals; they are endothermic ("warm-blooded"), breathe air and feed milk to their young. Blue Whales, like (almost) all mammals, give birth to live young – the biggest babies in the world. A newborn Blue Whale is as big as an elephant!

Links

MV Blog: Whale vs Shark

Megalodon: Fossil Shark Tooth

InfoSheet: Shark Teeth

InfoSheet: Blue Whale

Treasures: Blue Whale

Whale vs shark

Author
by Ursula
Publish date
7 February 2012
Comments
Comments (1)

Ursula Smith works in the natural sciences collections at Museum Victoria. Though a palaeontologist by training she finds all the collections fascinating and swings between excitement at all the cool stuff in them and despair at the lack of time to look at it all.

This cabinet contains parts of the skeleton of a fossil whale collected at Bells Beach, on the Surf Coast southwest of Melbourne.

collection cabinet Vertebrate Palaeontology Collection storage cabinet full of fossils.
Source: Museum Victoria
 

This story is only indirectly about that whale, but it does start with one of its bones:

Fossilised whale bone. Fossilised whale bone.
Source: Museum Victoria
 

This is a metacarpal – a bone from one of the whale's flippers (forelimbs). Here, it's being held by Dr Erich Fitzgerald, Senior Curator of Vertebrate Palaeontology and Harold Mitchell Fellow at Museum Victoria, which gives you an idea of the size – it's about 7cm long. The equivalent bone in a human hand (the bone that runs between your middle finger and your wrist) is about the same length, though not as chunky.

At the top of the bone, you can see two grooves that make an inverted 'V'. While they might not look particularly impressive, to Erich's eye that chevron shape was an immediate clue to something that's quite rare to find in the fossil record: it's a classic example of the marks left on bone by shark teeth. We know what a modern shark bite looks like from observing modern sharks and their prey, and the marks on this bone look just like the sorts of marks a modern shark bite makes. In the next photo, Erich is re-enacting the way a shark's tooth would make this sort of mark, (though obviously when a shark bites there are many more teeth involved).

Shark tooth and whale bone Erich demonstrates how a shark tooth probably struck the whale bone.
Source: Museum Victoria
 

While it's not absolutely conclusive evidence – this sort of palaeo-behaviour trace fossil rarely is – this, and other marks on other bones from the same specimen, is enough for us to be fairly certain that this whale was bitten by a shark. We also know that this happened very close to the whale's death because the bone shows no sign of healing. This tells us that either the whale was killed by the shark that attacked it or that the shark was scavenging the whale carcass after it died – we can't be sure which but we know that the whale wasn't bitten and then got away.

Even with this uncertainty, though, this is more information than palaeontologists usually have about interactions between animals in the fossil record. Information modern ecologists take for granted, such as who's eating who, is extremely rare to find for fossils. Bite marks like these are one of the few ways palaeontologists have any idea of how food webs may have been constructed way back when. But what's really cool about this particular whale/shark palaeo-interaction, is that rather than just being satisfied with 'this whale was attacked by a shark' we can actually figure out who the culprit was. A lot of work has been done on the geological unit that this specimen was collected from so we know what was sharing the waters with our luckless whale. Of the list of sharks known from the same unit, only one has teeth big enough to have made these marks:

Fossil shark tooth Fossil shark tooth.
Source: Museum Victoria
 

This tooth comes from the shark Carcharocles angustidens, known from relatively abundant fossils around the stretch of coast our whale was collected from. C. angustidens is a close relative of the rather more famous Carcharocles megalodon which has the largest teeth of any known shark, living or extinct (some are over 18cm long!) You can see the sharp little serrations along the edge of the tooth which would have effectively sawed into the bone of its victim, leaving the grooves we see in the whale's bones today.

So we think that somewhere in the Late Oligocene, 24-27 million years ago, in a sea that covered what is now part of Victoria, a shark, Carcharocles angustidens, bit a Mammalodon whale and perhaps even killed it. It's amazing what we can infer from just a few scratches on bone.

Links:

MV Blog: Evolving the biggest mouth in history

Footage of tiger sharks scavenging a whale carcass in Queensland

Footage of sharks eating a blue whale alive

What's that smell?

Author
by Kate C
Publish date
4 January 2011
Comments
Comments (6)

Every now and then, those of us who work at Melbourne Museum receive a polite but slightly troubling email:

"The Preparation Department needs to undertake work today that may generate some odours."

I can’t think of another workplace where stench warnings are a regular occurrence. They’re intriguing, too, because I always wonder what they’re doing down there in the basement.

Our skilled preparators do much as their name would suggest: they prepare things, from animal specimens for research collections to intricate models for display. Their job combines elements of biology, taxidermy, sculpture and painting and their work area is a den of creativity and practicality that is stocked with tools and equipment and art supplies.

In mid-December, a Gray’s Beaked Whale (Mesoplodon grayi) unfortunately was stranded at Portland and died. Given the rarity of this species, and MV’s strength in the study of whales, its skeleton is a valuable addition to our research collection. The preparators perform the somewhat gruesome but necessary task of cleaning the skeleton, and that’s where the odour comes in.

Gloves hanging in the Preparation Department The Preparation Department's collection of rubber gloves - essential tools in this line of work.
Source: Museum Victoria
 

Preparator Steven Sparrey explained the facilities in which large specimens are prepared. The specimens are placed in a sequence of water baths in the ominously named ‘maceration tank’ which allows the animal’s soft tissues to loosen away naturally from the bones without damaging them. It’s not pretty and it doesn’t smell good. After this, the bones are given a soapy wash and dried thoroughly.

Preparation Department The sealed room that holds the maceration tank (at the back) and cleaning benches.
Source: Museum Victoria
 

Some astonishingly large vertebrae from the backbone of a whale were on the drying racks. These were prepared for the Melbourne Aquarium from another stranded animal. The bones were quite yellow and Steven explained that the stains are from the whale’s oils, and they would be bleached by the sun once they were properly dry.

Whale vertebrae drying Whale vertebrae in the drying racks.
Source: Museum Victoria
 

Shortly after that, he firmly suggested that we leave the area because the smell tends to cling to clothing. Needless to say, he doesn’t wear his work clothes home on the train. So there you have it – perhaps not one of the most glamourous jobs at the museum, but an essential task to maintain Victoria’s collection of our state's fauna.

Links:

Model-making for Dynamic Earth

Climate change and whale evolution

Fossil unlocks secrets to the origin of whales

About this blog

Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.

Categories