Is it permissible to bring an animal for protection and guarding against thieves into a home where women live alone, and what animals are permissible for that purpose?

It is permissible to keep a dog for guarding outside the house, such as guarding crops and livestock. This can be extended to guarding houses and paths, due to the need for it. This is supported by the decrease in the daily reward for whoever keeps a dog for purposes other than these. One must be careful not to bring the dog inside the house, lest it prevent the angels from entering.