And last December, a New York family's pit bull mix, Kola, was presumed kidnapped after chasing intruders from her family's New City home. Kola, who had been adopted after being saved from a Yonkers, N.Y., dog fighting ring, according to New York affiliate WABC, was found tied to a signpost in New Jersey, injured, but safe.
Kola's owners, the Rosen family, told WABC that she had gone after the intruders when they tried to break in through a window. She chased them off the property, but then vanished.
Christensen said many dogs excel at identifying threats and protecting their "pack." Some breeds, including dobermans, German shepherds and rottweilers, have been bred specifically for that purpose.
While dogs like Penny are hailed as heroes, she said, that instinct can sometimes backfire when dogs feel the need to "protect" their owners and territory from things like the mailman or the Chinese food delivery guy.
"Every dog's an individual [in] what they're going to be willing, able and interested in doing in any given situation," Christensen said.