SeaMonster at Dubai Aquarium and Underwater Zoo?

[Raphus]

I am very sure sand tigers can breath actively. But I am no expert

 

[chris kippax]

Would anyone care to share a photo of one lay on the bottom?

I have dived with the Grey Nurse variant of this shark plenty of times. They do hang motionless in the water column at times but the current is helping them breath then.
I have never seen one lay on the sand like a White tip or Wobbegong and I believe if they did they would die.

 

[Dan]

Would anyone care to share a photo of one lay on the bottom?

I have dived with the Grey Nurse variant of this shark plenty of times. They do hang motionless in the water column at times but the current is helping them breath then.
I have never seen one lay on the sand like a White tip or Wobbegong and I believe if they did they would die.

When they are sleeping, they are hovering (not swimming) in perfect buoyancy and move their mouth to pump the water through their gills as shown in this Jonathan Bird’s Blue World video around 10-minute mark of the video.

 

[chris kippax]

Yep seen this quite a few times but always in open water so never witnessed the mouth ram breathing before. I have never seen them lay on the bottom.

 

[Dan]

I have seen them just hovering, with no current, inside a wreck. They move their mouth to breathe. It doesn’t matter whether they lay on the bottom or hover, these kinds of Sharks, like Whitetip Reef Sharks or Zebra or Nurse Sharks, can breathe in no current without swimming, by simply moving their mouths.

 

[chris kippax]

The reason it is ram breathing is because it is inside a wreck with no current.
These sharks do not lay on the bottom period (unless mortally ill)
These are requiem sharks and lack the spiracle of the other species you listed Dan.
The spiracle is what allows Rays, Nurse sharks and leopard sharks to lay on the bottom. A grey Nurse laying motionless on the bottom for an extended period is on deaths door.

 

[Dan]

The reason it is ram breathing is because it is inside a wreck with no current.
These sharks do not lay on the bottom period (unless mortally ill)
These are requiem sharks and lack the spiracle of the other species you listed Dan.
The spiracle is what allows Rays, Nurse sharks and leopard sharks to lay on the bottom. A grey Nurse laying motionless on the bottom for an extended period is on deaths door.

My bad. You are right. I learn something today. LOL.

Sand Tiger Sharks don’t have spiracles. They can only switch between modified buccal pumping and ram ventilation.

“Benthic Chondricthyes, such as a horn shark, round ray, or shovelnose guitarfish, live on the sea floor, with mouths located on the bottom of their heads to get food from the sand below them. Many of these animals also camouflage and avoid predation or sneak up on prey by burying themselves in the sand. In order to breathe without buccal pumping or ram ventilation, they use specialized holes behind their eyes called spiracles. Spiracles act like a straw or snorkel sticking out of the sand, drawing water over their gills and out the gill slits. This allows these animals to remain motionless and below the sand while still being able to get oxygen. If you look closely at a shovelnose guitarfish hiding in the sand on Catalina Island, you can actually see the spiracles opening and closing behind its eyes!”
Spiracles: The Secret of the Benthic Shark - Explore

 

[chris kippax]

My bad. You are right. I learn something today. LOL.

Sand Tiger Sharks don’t have spiracles. They can only switch between modified buccal pumping and ram ventilation.

“Benthic Chondricthyes, such as a horn shark, round ray, or shovelnose guitarfish, live on the sea floor, with mouths located on the bottom of their heads to get food from the sand below them. Many of these animals also camouflage and avoid predation or sneak up on prey by burying themselves in the sand. In order to breathe without buccal pumping or ram ventilation, they use specialized holes behind their eyes called spiracles. Spiracles act like a straw or snorkel sticking out of the sand, drawing water over their gills and out the gill slits. This allows these animals to remain motionless and below the sand while still being able to get oxygen. If you look closely at a shovelnose guitarfish hiding in the sand on Catalina Island, you can actually see the spiracles opening and closing behind its eyes!”
Spiracles: The Secret of the Benthic Shark - Explore

All good Dan
One of the best parts of Scubaboard is that I learn something most times I come here.
My wife is a senior aquarist at an aquarium that has 3 Grey Nurses in it. They only witness the buccal pumping when a shark is stressed. In Australia I have never seen one inside a wreck so what you have witnessed may be a very area specific behaviour. These sharks are quite an oddity though and seem to not conform to the rules most other sharks live by.

 

[RyanT]

These sharks do not lay on the bottom period (unless mortally ill)

Nah, we see perfectly healthy sharks laying on the bottom all the time. I've got a video, but it's too big to share on Scubaboard. If you're interested, let me know and I can upload a copy to dropbox for you.

 

[chris kippax]

Nah, we see perfectly healthy sharks laying on the bottom all the time. I've got a video, but it's too big to share on Scubaboard. If you're interested, let me know and I can upload a copy to dropbox for you.

Thanks Ryan
Just a screen shot or 2 will be fine, I have seen them hover an inch above the substrate but never lay on it.