Bites from Sydney funnel-web spiders have caused 13 documented deaths (seven in children). In all cases where the sex of the biting spider could be determined, it was found to be the male of the species. One member of the genus "Hadronyche", the northern tree-dwelling funnel-web spider, has also been claimed to cause fatal envenomation, but to date, this lacks the support of a specific medical report. Assays of venom from several "Hadronyche" species have shown it to be similar to "Atrax" venom.