Pizza, ‘world’s saddest polar bear,’ shows signs of mental decline in mall zoo

New footage of Pizza, a polar bear in a Chinese mall aquarium, has animal rights activists concerned for his mental health.

The video — released Tuesday by Humane Society International — shows Pizza (who has been dubbed the “world’s saddest polar bear”) pacing back and forth, swinging his head and clawing at the glass enclosure.

Alistair MacMillan, the veterinary advisor for HSI, said in a press release that these are signs “induced by frustration and poor welfare.”

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“This is the animal’s attempts to cope with stressful, aversive situations such as barren enclosures, boredom and constant disturbance by visitors,” he said. “The conditions in which he is being kept are completely unsuitable, vastly removed from anything approaching his natural habitat, and if something is not done then he will likely slip further and further into mental decline.”

Tweet This Click to share quote on Twitter: "This is the animal's attempts to cope with stressful, aversive situations such as barren enclosures, boredom and constant disturbance by visitors," he said. "The conditions in which he is being kept are completely unsuitable, vastly removed from anything approaching his natural habitat, and if something is not done then he will likely slip further and further into mental decline."

In September, Yorkshire Wildlife Park in the U.K. offered to bring Pizza to its outdoor animal sanctuary where they have a polar bear habitat.

WATCH: Last month, the Yorkshire Wildlife Park offered to take Pizza from the Grandview Mall

According to HSI, Chinese authorities and the Grandview Mall have rejected the proposal and now Chinese animal rights activists are working to negotiate Pizza’s release into a local sanctuary.

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“It is deeply disappointing that Yorkshire Wildlife Park’s proposal was refused, Pizza could have enjoyed enrichment and relative freedoms that are utterly impossible for him at the Grandview,” HSI’s Wendy Higgins wrote in an email. “However, our partner groups will be hoping to have dialogue with the Mall, and to explore alternative options on the Chinese mainland that may offer some hope.”

So far, 50 animal rights groups have collected one million signatures on a petition to permanently close the Grandview Mall’s aquarium.