pregnant nurseshark behavior

[pidgiepoo]

Does anyone have a good reference on the behavior of pregnant nursesharks? On one of my recent Cozumel dives, the DM pointed out a pregnant female under a ledge. When we got back on the boat he told me the pregnant female finds a "nest" and stays there for two weeks until the pups are born. Apparently, she doesn't even leave to hunt/eat the entire time. I'm trying to find out more info on this, as well as what happens to the pups. I'd really like to see a pic of some pups if someone has one. I heard they can have up to 30 at one time. Thanks

 

[mjatkins]

I am certainly no expert on this subject. I did however find this video of a nurse shark giving birth that might give you some insight. This one gave birth to one pup only, and it was an unexpected birth in an aquarium. That would lead me to think that if the shark had laid on the bottom for two straight weeks in preparation, the birth would probably not have been unexpected.

YouTube - Grey Nurse Shark Birth in Captivity at UnderWater World

 

[pidgiepoo]

Firstdive2005 sent me this info on the December in Cozumel thread :
"Nurse sharks can have up to 30 pups at birth. They are exact replicas of their mom. They dont nurse, they hunt right away. I have seen very small nurse sharks but never pups. They reproduce via aplacental viviparity."
That info and the DM's speech got me interested in finding out what I can about the subject. Still hoping someone can give me a good reference..if there's one available.
Thanks for the video..it was very interesting. I'm wondering if there are different behaviors in captivity vs natural environment??

 

[jfcl01]

They really like pickles and ice cream

 

[mjatkins]

I've been doing some more looking around, and it would appear that the video is of a "grey nurse shark" which is very different from the "nurse shark" that we have in Cozumel. The "grey nurse shark" is what we in N. America call a "sand tiger shark" (not to be confused with a "tiger shark"). Whew!

Although I haven't found any mention yet of them staying dormant for two weeks leading up to birth, I have found several sources that site them having batches of 20-28 babies on average. Possibly the best write up so far is this one Howstuffworks "How Nurse Sharks Work"

It has links to it's sources, so you can trace them down if you like.

Thanks for the post, I learned several new things today : )

 

[pidgiepoo]

. Possibly the best write up so far is this one Howstuffworks "How Nurse Sharks Work"

Thanks for the post, I learned several new things today : )

You are welcome...but you are the one who deserves the thanks. Your article and the video was great. Thanks to you I've learned lots about nurse sharks....but am still curious to see if anyone knows if that "nesting" info is correct. And what percentage of the pups survive after birth, since it appears other predators enjoy them on their dinner menu. Sounds like they would be an easy catch if they are as lazy as their parents !!