Spain’s Guggenheim museum has defended itself in the face of protest over the exhibition of two controversial Chinese artworks featuring animals, which had previously been withdrawn from its gallery in New York.

The original Guggenheim last year succumbed to fierce pressure to remove the installations, one featuring live reptiles and insects and another a video of two pigs copulating, from the exhibition “Art and China after 1989: The Theatre of the World”.

But the works will be on display when the 150-piece show comes to the Guggenheim in Bilbao from May 11, a decision which has drawn the ire of animal rights campaigners.

One work, Huang Yong Ping’s “The Theatre of the World” - for which the exhibition is named - features two cage-like structures containing toads, snakes, lizards, tortoises, beetles, cockroaches and other insects. Xu Bing’s “A Case Study of Transference”, shows a boar and a sow covered in Eastern and Western symbols copulating in front of a crowd of human onlookers.

More than 823,000 people have now signed a Change.org petition begun ahead of the New York show demanding the works be pulled.

Representatives of the Bilbao Guggenheim say the decision to display the works is about defending freedom of expression at a time when it is increasingly under threat.