African elephants living in a Pittsburgh zoo are increasingly stressed out by dogs that are used to control the animals and protect handlers, and this practice has sparked complaints from wildlife advocates.

Officials with the Pittsburgh Zoo & PPG Aquarium continue to defend their dog methods, even after the US Department of Agriculture (USDA) ordered them to stop. And now People for the Ethical Treatment of Animals (PETA) has filed a complaint, citing instances in a new report when a dog growled and lunged at one elephant, and entered the enclosure without being called.

According to the report, the zoo's manager even confirms that dogs have bitten elephants and have put these gentle giants under severe stress. Elephants flapping their ears, trumpeting and turning and running away - after being charged by the dogs - have demonstrated this.

"The Pittsburgh Zoo should be working to protect animals, employees and visitors by barring all direct contact with elephants, not digging in its heels and experimenting with dogs' lives for publicity and ticket sales," Brittany Peet, deputy director of captive animal law enforcement for PETA, told The Guardian.

And yet, despite the PETA complaint and USDA report asking the Pittsburgh zoo to cease these practices, it seems the institution has no intention of doing so.

"The introduction of the dogs has been a valuable tool as we continue to elevate the care and management of our elephant herd," said the zoo's president and chief executive, Dr. Barbara Baker.

"The safety of our keepers and animals is a top priority and we provide an additional safety level with the use of trained cattle dogs. The dogs read the behavior of the animals and alert the keepers to any disruption in the herd, preventing potential safety concerns for the staff and elephants," she added.

The zoo's dog herding program started and 2012, and since then no keepers, elephants or dogs have been injured. However, PETA plans to continue to press the issue until the zoo complies with the USDA's orders to "correct" their practices immediately.

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