ST. PAUL (AP) -- A Minnesota zoo is trying to help re-establish an endangered toad in Wyoming.

Como Zoo in St. Paul released 3,288 Wyoming toad tadpoles into the Laramie basin in southeastern Wyoming on June 17.

The Wyoming toad is remarkable for its small size. Adults often grow to only 2.5 inches long.

The toad was once common in the Laramie basin but officials say herbicides and pesticides have hurt the species' numbers. The U.S. Fish and Wildlife Service listed the toad as endangered in 1984.

Como Zoo is one of eight facilities nationally that breed the toads. Como Zoo spokesman Matt Reinartz says the June release was the zoo's largest to date.