The director of a zoo where a 17-year-old gorilla was shot dead has revealed it had taken frozen sperm from him so his 'gene pool' would continue.

Harambe, a western lowland silverback gorilla, was shot with a rifle when a four-year-old boy entered its enclosure on Saturday.

Zoo director Thomas Maynard said the child - who has not been named - was in imminent danger because the gorilla was disorientated and confused.

This is despite video clips appearing to show Harambe standing guard over the child and even holding his hand.

The zoo shot the beloved animal after he dragged the boy through the water and up out of the moat - after Harambe's death frozen sperm was taken from him so his gene pool would continue

The incident has sparked a backlash around the world - both of the zoo's actions and of the apparent negligence of family members who failed to stop the boy.

More than 290,000 have now signed a petition calling for 'Justice for Harambe' which lays blame squarely with the child's parents.

But Mr Maynard - who defended the zoo's decision to shoot the gorilla - has insisted 'there is a future' for Harambe because 'it's not the end of his gene pool'.

Harambe, who was 17, had not been mature enough to breed but his sperm was collected after his death for possible future reproductive use, as well as for research purposes.

Western Iowland gorillas are critically endangered in the wild - in the dense rain forests of Cameroon, the Central African Republic, the Democratic Republic of Congo and Equatorial Guinea - where their numbers have declined by more than 60 per cent over the last 20 to 25 years.

Their numbers are now estimated at fewer than 175,000.

The Cincinnati Zoo has a long history of breeding gorillas. Fifty gorilla babies have been born at the zoo in the past 46 years.

Harambe was born in captivity in Texas and moved to Cincinnati zoo in 2014, where it was hoped he could be part of that breeding programme.

During Monday's press conference, Maynard supported the animal response team's decision to kill Harambe, and said: 'Looking back we would make the same decision'

Speaking at a press conference yesterday, Mr Maynard defended the zoo's controversial decision to shoot Harambe.

He said: 'This child was being dragged around and his head was banging on the concrete. This was not a gentle thing.

'We did not take the shooting lightly. But that child's life was in danger and people who question that, or are Monday morning quarterbacks or second guessers, don't understand that you can't take a risk with a silverback gorilla.'

The huge gorilla was about six times stronger than a man, he added, and was confused and agitated.

'This is an animal (that) with one hand, I have seen take a coconut and crush it,' he said.

Mr Maynard said tranquilizing the prize ape was not an option because a dart could have startled the creature, causing it to act aggressively before the sedative kicked in.

He added: 'Looking back, we would make the same decision. We are heartbroken about losing Harambe, but a child's life was in danger and a quick decision had to be made.'

Flowers are placed at a bronze statue of a gorilla outside Cincinnati Zoo's gorilla world exhibit yesterday

A boy bows his head in front of the bronze gorilla statue as tributes are paid to Harambe, who was shot dead

Harambe's death has sparked an outcry of emotion, with thousands of mourners branding it a 'senseless death' (pictured, Monday's vigil)

The boy had climbed the 3ft-tall barrier and crawled through the bushes before falling 15 feet (4.5 meters) into the enclosure on Saturday.

He was treated at a hospital and released that same day.

In a statement on Sunday the family said: 'We are so thankful to the Lord that our child is safe. He is home and doing just fine. We extend our heartfelt thanks for the quick action by the Cincinnati Zoo staff.

'We know that this was a very difficult decision for them, and that they are grieving the loss of their gorilla. We hope that you will respect our privacy at this time.'