People for the Ethical Treatment of Animals (PETA) has requested that the NHL ice hockey league ban live animals from its games, after penguins appeared during the Stadium Series game in Pittsburgh.

In a letter to NHL commissioner Gary Bettman, PETA criticised the Pittsburgh Penguins’ use of live penguins, claiming the animals “scrambled in terror” when fireworks were set off.

“It’s inherently stressful for wild animals to be paraded around in front of a raucous crowd, and the public has overwhelmingly spoken out against abusing animals for entertainment,” said PETA executive vice-president Tracy Reiman.

“PETA is urging the NHL to make it clear that live animals do not belong in the arena.”

Also involved in the preparation of the pre-game show was the Pittsburgh Zoo and PPG Aquarium that said they worked with NHL officials to ensure the animals’ safety, which is its main priority.

Following the game against the Philadelphia Flyers, PETA representatives wrote to the team with its request to avoid using live animals at Heinz Field ever again, a plea it has now extended to the NHL.