The wandering spiders are the members of the spider family Ctenidae. Previously, the term referred only to the genusPhoneutria but now usually refers to the entire family Ctenidae. The members of the genus Phoneutria are highly aggressive and venomous nocturnal hunters, and are the only wandering spiders known to pose a serious danger to humans. However, the venom of some other members of this family is very poorly known, meaning that all larger ctenids should be treated with caution. Some ctenids have marks and patterns that are attractive. Ctenids have a distinctive longitudinal groove on the top-rear of their oval carapace (some other spiders have a similar groove; e.g., Amaurobiidae).