Suspected brown and black widow spiders discovered at the Guam Port

Spiders found in Port’s warehouse

March 12, 2026Updated: March 12, 2026
By Jason Salas

An established population of highly venomous black widow spiders and their less dangerous cousins brown widows were discovered at the Guam Port today.  Department of Agriculture biosecurity chief and state entomologist Christopher Rosario tells KUAM News the spiders were found in the Port’s warehouse where inspections are conducted. 

Rosario says “it’s likely been a while” that the spiders were there. 

Agriculture’s Biosecurity Team in coordination with the Port Authority of Guam conducted rapid response treatment at the warehouse and did not find any more spiders. 

Black widows are highly venomous and can cause severe pain and illness. According to the National Capital Poison Center, their bites can be dangerous, especially to young children and elderly people, but fatal bites are rare.

Brown widows are generally not considered deadly. 

After his review, University of Guam’s assistant professor of entomology Dr. Daniel Johnson has confirmed with Biosecurity that what was suspected to be black widows are all brown widows - their less dangerous cousins.