Vegan and animal-rights activist, Abbie Andrews, created a petition urging the zoo to cancel the event, receiving nearly 500 signatures in under 24 hours.
'No care for the animals'
"This is a recurring event where the zoo is basically turned into a nightclub for the night, with music blaring and alcohol being sold, with no care for the animals and with countless incidents in previous years," Andrews said.
The petition claims previous incidents that have occurred at the zoo include people trying to enter enclosures, people pouring beer over Tigers, Penguins being chased and allegedly harmed, and Butterflies being crushed.
'Absolutely no consideration'
"There is absolutely no consideration for the animals who are already kept at the zoo against their will, it is all for consumers," the petition reads.
"The last thing these animals need is to be surrounded by drunk people and loud music. This event has been rebranded several times with no indication of it being canceled for good."
Andrews is urging the public to sign the petition before June, where the event will take place every Friday of the month.
ZLS London Zoo said: "We have strict measures in place and animal welfare is always a top priority when planning events. At every Zoo Nights event we have an animal welfare officer present along with our expert zookeepers who care for our animals. We also monitor sound levels and ensure we continuously adhere to all relevant policies.
"At ZSL London Zoo, our animals come first. During the day, or at special events, our expert vets, devoted zookeepers and specialist animal welfare officers are dedicated to ensuring that we provide everything they need to stay healthy, stimulated and fit."
The zoo also claimed the alleged incidents were 'heavily sensationalised news reports' and that 'no visitor ever injured an animal nor got into an animal enclosure'.
* This article was updated on May 24 after ZSL London Zoo replied to Plant Based News' questions.