A video that shows a visitor climbing into an enclosure at a zoo and slapping a hippo has sparked fury.

The bizarre footage shows a man at Los Angeles Zoo slowly make his way over the fence and gesture to the camera to be quiet before he reaches down to spank a hippos backside.

A loud slap can be heard before the man quickly runs out the enclosure and celebrates with a dance to the camera by waving his arms in the air.

A man has sparked fury after he is filmed climbing into a hippos enclosure at Los Angeles Zoo and spanking one of the hippos

The man can be seen slowly creeping up on the animals before leaning over and slapping Rosie the four-year-old hippo's backside

A woman filming can be heard saying: 'He just slapped the hippos ass.'

The two hippo's in the enclosure, four-year-old Rosie and her mother Mara, were calmly standing by some water.

Younger hippo Rosie, who was slapped, appeared to look startled by the sudden contact.

News Week reported that a the Los Angeles Police Department (LAPD) has launched an investigation for trespassing.

The LAPD said it was not being considered a case of animal cruelty because the hippo's were not harmed, although the spanking could have caused stress.

April Spurlock, a spokeswoman for the zoo told The Los Angeles Times: 'Every animal is different and we don't know exactly what they were thinking.

A police investigation has been launched for trespassing after the video emerged and caused outrage with zoo staff

A spokeswoman for the zoo that 'every animal is different and we don't know exactly what they were thinking'

'But, it's an invasion of the trust we work so hard to build with these animals.

'We seriously feel this was an isolated incident.'

'Most people know not to go in with the animals. It's common sense.'

The zoo has now installed it's first 'No Trespassing' sign near the hippo's enclosure.

Despite appearing docile in this video, hippos are one of the most dangerous species in the world and have killed more people than any other large animal in Africa.