Shark vs. Dinosaur

A recent find in Utah reveals a large prehistoric lake around 200 million years with an amazing fossil cache including an enormous, carnivorous dinosaur and several species of sharks. Anatomical features of the dinosaur suggest it specialized in eating fish, including sharks and huge bony fish, meals which palaeontologist James Kirkland describes as “like biting through chain mail [since] fish in the past were more armored than they are today."

The dinosaur, a relative of the crested dino Dilophosaurus, was about 20 feet long and so would have been a formidable adversary for its ferocious prey. The dinosaur’s slender, serrated teeth are quite unusual and only found in dinosaurs like Spinosaurus and Suchimimus.

Dilophosaurus was well adapted to being a fisherman. Its nasal openings retracted back from the end of its snout so that it could, like today's crocodiles and alligators, still breath when its mouth was underwater.

There are clear tracks and claw scrapes showing the dinosaur wading into the lake to catch its prey. "We have counted over 3,000 individual claw marks and toe scrapes that show incredibly detailed preservation," reveals palaeontologist Andrew Milner. "We can see details of cuticle on the tips of claws, skin impressions, scale scratch lines and where claw cuticle was overlapped by the fleshy toe pads at the end of the toes."

Why do Great White Sharks always have a big bloody gape?

Something has been bothering me the last while. I can’t figure out why Great White Sharks are always depicted as having a big bloody gape? I have researched it a bit but have not come up with any good information. As it I see it though, there are three distinct possibilities:

1. The big bloody gape is a fallacy propagated by Hollywood
2. Blood is leftover from a kill
3. The blood is their own

There are few points to be noted about each possibility:

1. Purusing some stock photography (seen below) it seems that there a a mix of shark pictures, with and without bloody mouths. And of course, this may be subject to a photographer’s bias.

2. If the blood is indeed from a kill, why would it stain so long and not simply wash away? Also, it should be noted that Great Whites don't eat that often.

3. If the blood is their own, why doesn’t it attract other sharks?

If you have comments on this topic, please let me know, I would like to solve this mystery!

Denizens of Deep Seas and Deep Time Part1: The Frilled Shark & Goblin Shark

‘Living Fossil’ is often a term applied to an animal that has a fossil record very far back in time but no close living relatives. This is a loose definition and taxonomists will argue about its specifics but we aren’t going to hash it out. Most people have at some point or another have heard of living fossils and you could probably come up with a list of common suspects: gingko, horsetail, horseshoe crabs, sphenodonts and the platypus, an egg-laying mammal. A popular theory has also pegged the Loch Ness Monster as worthy of living fossil status since it is ‘a plesiosaur trapped in time’. But you needn’t look to legend and mythology to discover sea monsters that are living fossils because we are still finding them today. This is the first in a three part series about Frilled & Goblin Sharks, Coelacanths, and Vampire Squids.

Sharks evolved about 400 million years ago and so they have had a lot of time to adapt and change to their environment. Their great diversity is familiar to us all: from the fearsome gape of the Great White to the bizarre, almost laughable appearance of the Hammerhead. Sharks as a whole group have been called living fossils, though the term is probably best applied to specific species which have changed very little through time and have few relatives.

Recently, two amazing discoveries of living fossil sharks were made off of the coast of Japan. On January 21, 2007, staff at Awashima Marine Park in Shizuoka, southwest of Tokyo, were alerted by fishermen to a 'strange eel-like fish with razor sharp teeth'. The 1.6 meter long female frilled shark appeared to be in poor health so was captured by park staff who placed it in a salt water tank. Unfortunately, the fish died a few hours after capture.

The frilled shark (Chlamydoselachus anguineus) was discovered in Japanese waters in the 19th century and superficially, looks less like a shark and more like an eel. Its distinctive 'shark' features include its eponymous protruding gill slits which form a frill around its neck The frilled shark usually live at depths of 600 to 1,300 meters, feeding on small deep water fishes and squid. Park staff believe the animal came to the surface because it was unwell and disoriented.

More recently, another strange creature, a 1.3 metres long goblin shark was caught swimming in Tokyo Bay. It was transferred to an aquarium but also died a short time later. The goblin shark (Mitsukurina owstoni) has a long pointed, rostrum and dwells at similar depths to the frill shark feeding on small fishes and crustaceans. The most striking feature of this odd animal is the snout which is thought to be an electrosensory device used to detect prey for capture.

Both the frilled and goblin sharks are so rare that only a few have ever been documented and studied since thier discovery in the 1800s. Their homes are so deep in the oceans that we cannot easily study their habitat, life history and reproductive habits. Ironically though we cannot reach them, it is likely that the polluting effects of our lifestyles reach their environment. But since we cannot determine if their populations are threatened by our actions they are not currently given protected status.