PITTSBURGH — The Pittsburgh Zoo & PPG Aquarium says the mother of a 2-year-old boy fatally mauled in a wild African dogs exhibit is to blame in her son’s death and shouldn’t be allowed to sue.

The claim filed Monday in Allegheny County is in response to a lawsuit brought by the parents of Maddox Derkosh.

Jason and Elizabeth Derkosh are seeking unspecified damages in the Nov. 4 death of Maddox, who fell over a 4-foot-tall railing into the exhibit after his mother lifted him up to get a better look.

The zoo says in the court filing that Maddox’s death was “caused solely by the carelessness, negligence and/or recklessness of Elizabeth Derkosh.”