She is probably a Brown Widow, Latrodectus geometricus. The spiky white egg sacs are a characteristic trait of the species. Her underside should have a orange-red mark. The spiders in genus Latrodectus have dangerous venom. Please see a doctor if you are bitten. There is anti-venom for Latrodectism. Like most spiders, they are not aggressive toward humans and other large animals except if the eggs or babies are handled. They probably won’t bite except in self-defense. Pressing skin against them can hurt them and they may bite to make it stop. Wearing work gloves when you reach into dark places… Read more »
Thanks so much for the response. She’s made her nest against my second garage door which I only open occasionally. I take care not to roll the door all the way up as to avoid hurting her.
I took another photo of her hanging upside down and can confirm the orange marking.
My kids generally stay out of the garage but should we be cautious that there may be more elsewhere in the garage? Or are they territorial?
Sorry for the delay in responding. Yes there may be others in the area. I don’t think one spider would be able to keep others away from much of the area. My own spiders in that family avoid each other but each only has a radius of about 2 meters of its own. The hatchlings probably spread out to avoid being eaten by each other. So, there should be a low population density, but you should be careful about reaching into dark places anywhere in the area.