Egg Sac help!


Old Timer
Aug 7, 2002
Hi, I am writing this to help out a newbie friend who has these questions, and also for me because i do not know the answers and i am curious.

He has a rosehair (g.rosea) that made an egg sack (describes it as some sort of sac that looks like a tight cotton ball so i told him it was an egg sac). It was made 4-5 days ago and he and i would like to know when he can expect it to hatch? If he can/should take the sac away from the tarantula? what do do when it hatches and he has hundreds of baby t's running around? Keep in mind he is a newbie and recieved this tarantula from a friend not knowing it was gravid.

Answers to these questions would be greatly appreciated as would any info on what to do with hundreds of baby tarantulas.




Old Timer
Jul 19, 2002
I'll provide what information I learned when my Costa Rican Zebra produced an egg sac earlier this year.
It's important to leave the eggsac with the mother for at least the first 30 days. This is the period where it needs round the clock attention. You'll notice she will continually hold it and will turn it at times during the day.
If possible, you should think of leaving the eggsac with the mother for the entire duration. I made the mistake of taking the egg sac from my Costa Rican Zebra, but in hind sight, I probably should have left it with her. You always run the risk of her eating it though.
Make sure she is in a location that is quiet. She should not be disturbed as this may cause her to feel threatened and cause her to eat the egg sac. Give her as much isolation as possible.
As for duration/number of spiderlings/huimidity, I'm going to have to defer to someone else, as these I believe would vary by spider.
One final note, tarantula's sometime make unfertilized egg sacs. This is what happened with my Costa Rican Zebra. When I opened the egg sac, it was full of eggs, but none ever developed. I'm not sure if there were never fertilized, or if they just never developed.
Hope this helps some.


Old Timer
Aug 16, 2002
I think the rough average is around 2 months, but this can vary alot, especially depending on temperature.

Although newly imported females have often mated before capture and drop fertile sacs, if this female has ever molted while in captivity, she must mate with a male again to produce a fertile sac. If she hasn't, the eggs will be duds. This is fairly common. Any stored sperm is lost during the molt, and she doesn't fertilize the eggs (using the stored sperm) them until she lays them.

Some keepers will pull sacs and incubate them away from mom, but since your friend is new, it might be best to just leave them with mom for now. The thing to worry about is if the spiderlings can escape from the cage mom is in. Usually, they stick close to the sac for awhile after emerging, but eventually the will disperse.



Old Timer
Jul 17, 2002
the only experience I have is with my B albopilosum...she has turned out to be a very good mom. The spiderlings emerged after 70 days, and they are now just molting into 2nd instar. They are still clustered around the eggsac, but I figure I have less than a week to start separting, and then all hell will break loose!
I have mom in a 15 gallon tub, with a mesh top. The mesh top is almost completely covered with saran wrap, keeping the relative humidity about 70-75%, and keeping the substrate dry, with a large water dish.
Temps varied a bit, but I'd say 80 degrees was fairly constant.
I didn't want to attempt incubating myself, I just didn't have the experience for it.
I kept her in an unused room, with minimal disturbance.
Hope that helps a bit