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bighairyfarrier
144832.  Fri Feb 09, 2007 2:19 pm Reply with quote

As far as I know the 'Meglodon' or lat, Carcharodon megalodon was the largest predetory fish ever to live, and was of the same family as the great white only much larger.

 
HasBeany
151408.  Sun Feb 25, 2007 5:56 pm Reply with quote

Shock Horror!
According to this evening's Natural World, the lovely Mr Attenborough stated that the ragged tooth shark [also called sandtiger shark] was the only species which evinces intra-uterine cannibalism. But when I trawled the net [what an appropriate phrase] ... I found this:

Quote from: http://www.elasmo-research.org/education/topics/lh_intrauterine_cannibalism.htm

Two forms of within-the-womb cannibalism are known in sharks. The most extreme form of intrauterine cannibalism - in which the largest and strongest embryo actually consumes its lesser womb-mates - is termed "embryophagy" or, more colorfully, "adelphophagy" - literally "eating one's brother". It was discovered accidentally in 1948, when a researcher probing the uteri of a late-term Sandtiger Shark (Carcharias taurus) was startled by a bite on the hand. To date, adelphophagy is known only in the Sandtiger. The less extreme and by far more common form of intrauterine cannibalism - in which developing embryos feed on a steady supply of tiny, unfertilized eggs - is termed "oophagy" (sometimes called "oviphagy") - meaning "egg-eating". The earliest documented case of oophagy dates back to 1907, in the Porbeagle (Lamna nasus). Both forms of intrauterine cannibalism continue throughout embryonic and fetal development, so that at birth each pups often has aa conspicuously swollen abdomen known as a "yolk stomach".

Until quite recently, intrauterine cannibalism was thought to be restricted to lamnoid sharks. This grisly form of within-the-womb nutrition is now known from two carcharhinoids and even one orectoloboid. Following is a list of all sharks in which intrauterine cannibalism has been documented, or for which exists strong circumstantial evidence:

Order Orectolobiformes

Family Ginglymostomatidae

Tawny Nurse Shark (Nebrius ferrigineus)

Order Lamniformes

Family Carchariidae

Sandtiger Shark (Carcharias taurus)

Family Pseudocarchariidae

Crocodile Shark (Pseudocarcharias kamoharai)

Family Alopiidae

Pelagic Thresher Shark (Alopias pelagicus)
Bigeye Thresher Shark (Alopias suprciliosus)
Common Thresher Shark (Alopias vulpinus)

Family Cetorhinidae

Basking Shark (Cetorhinus maximus)

Family Lamnidae

Salmon Shark (Lamna ditropis)
Porbeagle (Lamna nasus)
White Shark (Carcharodon carcharias)
Shortfin Mako (Isurus oxyrinchus)
Longfin Mako (Isurus paucus)

Order Carcharhiniformes

Family Pseudotriakidae

Slender Smoothhound Shark (Gollum attenuatus)
False Catshark (Pseudotriakis microdon)


Well I never!!!!

 
Mulvil
151553.  Mon Feb 26, 2007 8:39 am Reply with quote

The Bull Shark is the only shark that can tolerate both freshwater and seawater and bull sharks have been found as far upstream as baghdad in iraq.

They stay in shallow coastal waters as well as being found in rivers and lakes.

It is thought that many of the attacks on humans that are attributed to great whites are in fact the work of bull sharks which are, as previously stated, fond of shallow coastal waters, river mouths, bays, rivers and lakes, where humans may be found swimming.

They are also often called the Zambezi shark, the Ganges sharks and the Nicaragua shark.

Quote:
Interestingly, they are more docile when found in clear water habitats and are increasingly encountered by divers, without incident.



http://www.bbc.co.uk/nature/wildfacts/factfiles/181.shtml



http://www.sharkdiving.us/bullshark.html

 
Mulvil
203419.  Thu Aug 23, 2007 5:30 pm Reply with quote

And then there is the parthenogenesis that has recently been observed in Hammerhead sharks.

That is to say there has been a virgin birth. A shark in a zoo gave birth in 2001 with no apparent contact with a male. And just to prove there was no accidental contact the pup was DNA tested and ONLY maternal DNA was found.

I'm sure a lot of you already knew this and I've been meaning to post it for a while.

http://news.bbc.co.uk/2/hi/science/nature/6681793.stm

Also recently watching a documentary I saw the host standing in a shallow pool of water with a behavioural expert, surrounded by Bull sharks. I was thinking "well thats stupid, bull sharks are extremely unpredictable".

Anyway the expert said something along the lines of "if we just stand here they'll recognise we're not a threat and the won't attack us" (or something to that affect). One large female then proceded to remove the calf of his leg.


Anyone else enjoying shark week on discovery?

 
k.bygrave
224051.  Fri Oct 26, 2007 9:42 am Reply with quote

[quote="Mulvil"]They are also often called the Zambezi shark, the Ganges sharks and the Nicaragua shark.


Bull sharks are notorious in the Ganges, as people traditionally float thier dead relatives down the Ganges, with obvious benefits to the sharks

 
k.bygrave
224060.  Fri Oct 26, 2007 9:51 am Reply with quote

[quote="Hans Mof"]Only four species of shark are known to fatally attack humans: great white, bull shark, tiger, oceanic whitetip.

Interesting fact about oceanic white tips - they are usually the first species present when boats are sinking or planes have crashed over water and this is why they are considered dangerous to humans.

 
longwing
778465.  Fri Jan 21, 2011 12:14 pm Reply with quote

I learnt today during my self-teach course that shark skin used to be sold to use as sandpaper. I felt a piece - certainly when dried it would make good sandpaper and it has different grades depending on wherabouts on the shark you get it from. The scales are very hard, bony and sharp. They come in a range of sizes from minute to rather large.

 
Jenny
778471.  Fri Jan 21, 2011 12:48 pm Reply with quote

Shark skin is also used to make a kind of leather called shagreen, though they grind down the rougher bits for that.

Welcome longwing :-)

 
geplw
1283653.  Wed May 09, 2018 6:29 am Reply with quote

First post, hope its in the right place!

Jazz music is used to condition sharks

Quote:
Researchers trained baby Port Jackson sharks to associate music with a food reward. When played a jazz song, the sharks learnt to go to a feeding station for a tasty treat.


They were, however, more confused by classical music, perhaps due to underdeveloped training.

My favourite observation from one of the researchers at the Fish Lab, Macquarie University, was

Quote:
"Gaining a better understanding of this will help grow positive public opinion of sharks and may shift public and political will towards their conservation."


[url] https://phys.org/news/2018-05-sharks-jazz-music.html [/url]
[url] http://thefishlab.com/ [/url]
[url] https://link.springer.com/article/10.1007%2Fs10071-018-1183-1 [/url]

 
AlmondFacialBar
1283690.  Wed May 09, 2018 1:09 pm Reply with quote

Right... Yeah, grand, I know you wanna eat me, but at least we both like Chet Baker, right? I fear the researchers are leaving something vital out of that calculation...

:-)

AlmondFacialBar

 
Bondee
1283757.  Thu May 10, 2018 1:30 pm Reply with quote

I wonder what would happen if they played this to a shark.

 
DVD Smith
1292376.  Thu Aug 09, 2018 3:23 pm Reply with quote

What's the difference between a catshark and a dogfish? Nothing. [1]

Was looking into the quagga cat shark for the Q Series forum, and I got lost in the world of shark names. What I love about the quagga catshark is that it's an animal named after three animals (quagga-cat-shark). I wondered, can three be beaten? So I started looking at the long list of shark names and found the following, all with three animal names:

Boa cat shark
Tiger cat shark
Mouse cat shark
Gecko cat shark
Salamander cat shark
Leopard cat shark
Lizard cat shark
Bird-beak dogfish
Viper dogfish shark

Boom, we have a four-animal name!

Well, technically it's just the "viper dogfish" or "viper shark", but some places refer to it as the "viper dogfish shark" (including National Geographic at the link below) so I'm claiming it ^_^

The viper dogfish shark caused a stir in January 2018 when it was caught off the coast of Taiwan and people started comparing it to one of the creatures from Alien - because it has a detachable extendable jaw that makes it look like it has a row of teeth on its tongue. [2] [3]



I also found these sharks which I found interesting/amusing:

Swell shark - defends itself by basically becoming a rubber ring, by biting its tail and swelling to twice its size. [4]

Ninja lanternshark - named for its all-black colour with white eyes and mouth, and takes its Latin name Etmoperus benchleyi from Peter Benchley, the author of Jaws.

Arabian carpet shark - presumably helping Aladdin in his undersea adventures.

Gollum shark - named after the Tolkien character which which it "shares many similarities"

Lollipop catshark - Massive head and long narrow body. [5]

Phallic cat shark - Named for its huge penis.

Ghost shark - Has a penis on its forehead.

 
Baryonyx
1292779.  Tue Aug 14, 2018 5:19 am Reply with quote

For anyone who wants some more, I had a quick look at expanding the list to fish.

https://en.wikipedia.org/wiki/List_of_fish_named_after_animals

Favourites include:
Horseface Unicornfish
Cockatoo Waspfish
Raccoon Butterflyfish
and Bombay Duck which is actually a lizardfish


But then again, there is no such thing as a fish...

 

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