The allegations were in response to a lawsuit filed this year by the parents of Maddox Derkosh, who died last November after he fell into the African painted dogs enclosure, the Pittsburgh Post-Gazette reported Wednesday.
The cross claim filed by Dennis St. J. Mulvihill, an attorney for the zoo, charges the child's death was caused "solely by the carelessness, negligence and/or recklessness" of Elizabeth Derkosh.
The mother and child were standing on the enclosure's viewing platform when Maddox fell over the railing and bounced off protective netting into the enclosure where he was attacked by 11 of the animals.
Mulvihill alleged Elizabeth Derkosh had placed the boy on top of or over the railing.
The wrongful death lawsuit filed by Derkosh, 34, and her husband, Jason, 37, in May charges the zoo "blatantly ignored" warnings by zoo employees of the danger posed by parents lifting children onto or over the platform's railing, the Pittsburgh Tribune-Review reported.
An autopsy found the child survived the fall but bled to death after being attacked by the dogs.
The zoo also responded to claims in the Derkoshes suit, saying the railing met building and safety codes, the zoo did not have outdated tranquilizer darts and the viewing area was not unprotected, the Post-Gazette reported.