Pictured: Boy, 2, mauled to death at zoo after falling into African wild dog pit

Maddox Derkosh fell over railing about 12pm on Sunday at Pittsburgh Zoo and Aquarium

Dogs developed 'pack mentality' and could not be stopped by zookeepers who fired darts at them

Police officer opened fire and killed one dog that would not stop mauling boy

Both parents are currently being medicated to deal with shock



This is the tragic two-year-old boy who was mauled to death by a pack of ravenous African wild dogs after he fell off a zoo railing his mother put him on to get a better view of the animals on Sunday.



Maddox Derkosh had 'no chance' of surviving after falling 11 feet into the dog pit at the Pittsburgh Zoo and Aquarium while his horrified parents Jason and Elizabeth Derkosh looked on helpless.



Desperate rescue attempts by zookeepers and armed police officers could not deter the 11 aggressive beasts as they savagely attacked the two-year-old, from Pleasant Hills, on Sunday morning.



A medical examiner concluded today that the toddler was killed by the animals, not by the fall.

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Victim: Maddox Derkosh, two, was killed after falling 11 feet into the dog pit at the Pittsburgh Zoo and Aquarium.

Deadly hunters: Zoo chiefs decided to release the calendars despite the tragic death Scene: The overlook platform where the boy fell into the exhibit that was home to a pack of African painted dogs is seen through a window from another observation area at the Pittsburgh Zoo and PPG Aquarium Where: This is the overlook platform where two-year-old Maddox fell into the dog enclosure. He bounced off the net, which is there to save small items like cameras and phones

Barbara Baker, CEO and president of the Pittsburgh Zoo and PPG Aquarium said there is a net below the rail, but the boy bounced off it and into the enclosure.



She said the animals attacked the child so quickly that by the time a veterinarian and other zoo staffers arrived seconds later, they determined it would have been futile to try to rescue the child.



Authorities said that zoo staff and then police responded 'within minutes' but visitors described that time as being filled with screams for help.



Zookeepers called off some of the dogs, and seven of them immediately went to a back building.



THE 'PAINTED WOLF': THE MOST POWERFUL BITE OF ANY CARNIVORE

The African wild dog is an endangered species which typically roams the open plains and sparse woodlands of sub-Saharan Africa. The dog's Latin name Lycaon pictus means 'painted wolf' because of the animal's patchy colored coat of red, black, brown, white and yellow fur, each with their own unique pattern.

These dogs are very social, and packs have been known to share food and to assist weak or ill members. In fact after a successful hunt, the dogs regurgitate meat for those that remained at the den.

They hunt in packs of six to 20 and despite their small size they prey on large animals like antelopes and wildebeests.

They kill the larger prey by disemboweling, a technique that is rapid but has caused this species to have a negative, ferocious reputation.

They are often hunted and killed by farmers who fear for their domestic animals and are susceptible to diseases spread by domestic animals. Its large teeth allow it to consume a lot of bone in the same way a hyena does and it has a bite force quotient - BFQ, the strength of bite relative to the animal's mass - measured at 142, the highest of any carnivore, except for the Tasmanian devil. They are extremely aggressive and nearly 80 per cent of their hunts end in a kill - as opposed to a lion with a success rate of just 30 percent. There were once approximately 500,000 African wild dogs in 39 countries, and packs of 100 or more were not uncommon. Now there are only about 3,000-5,500 in fewer than 25 countries



Three more eventually were drawn away from the child and one especially aggressive dog refused to back down and stop attacking the boy.



It was shot dead by an officer. Experts said the death is highly unusual.

The family's neighbor Rachel Majcher told the Tribune Review: '(Jason and Elizabeth) went nowhere without Maddox. I cannot imagine the dark cloud that is following them.'

'I can’t imagine as a mom myself what tragedy that would be, Your heart stops when your kid skins a knee.'



She said her father saw Maddox trick-or-treating in a Superman costume, and he could often be found playing on a swing set with his cousin, who lives nearby.



'The hardest part is going to be to explain to my kids that their playmate is no longer here. His life will be celebrated.'

Steve Feldman, a spokesman for the Association of Zoos and Aquariums, said no one he's spoken to can recall any deaths of children at an accredited zoo over the last 40 years or more.



Feldman said the Pittsburgh Zoo successfully completed its five-year review in September, which means it meets or exceeds all safety standards.



The zoo was immediately closed, and it was not clear when it will reopen, authorities said.



The so-called painted dogs are about as big as medium-sized domestic dogs, and 37 to 80 pounds , according to the zoo. They have large, rounded ears and dark brown circles around their eyes and are considered endangered.



The attack happened in a 1.5 acre exhibit called the Painted Dog Bush Camp that's part of a larger open area where elephants, lions and other animals can be seen. Visitors walk onto a deck that is glassed on the sides, but open in front where the roughly four-foot railing is located.



In May, some of the dogs crawled under a fence and escaped into a part of the exhibit that's usually closed. The zoo was on lockdown for about an hour as a precaution.



Kraus said there was nothing to prevent visitors to the painted dog exhibit from jumping into the exhibit area. He described the accident as 'horrific'.



'Unfortunately, the dogs were in pack mentality and not responding to zookeepers' efforts to control them,' the zoo said in a statement.

Police and the Allegheny County medical examiner's office are investigating, and they haven't yet interviewed the mother or father, who are receiving grief counseling.



Baker said the zoo, which has never had a visitor death, will also investigate. She said no decision has been made yet on the future of the exhibit.



Emergency: ThePittsburgh Zoo's entrance is seen after the young boy was killed after falling into the exhibit around noon

Lock-dock: The zoo immediately closed and patrons were hurried inside buildings during the attack

Deadly: The dogs, which are smaller than Labrador retrievers, can be dangerous on their own but are deadly killers when hunting in packs



Zoo officials said there is a mesh barrier beyond the railing, but Lt Kraus said it was designed to catch small objects such as cameras, and not humans. Investigators have not determined the exact cause of death, he said.



'The screams just kept coming and coming: "Someone help. Someone has to do something,''' witness Angela Cinti, 20, who was visiting the zoowith her boyfriend told the Pittsburgh-Post Gazette.

'We were on our way to the polar bear exhibit when we heard the most horrible piercing screams,' Ms Ciniti recalled. 'Someone was begging for help, asking someone to do something.'

Guests recounted being hurried into the nearest building for safety, waiting for a half an hour according to Ms Cinit.

'We were locked down in the building and told to stay inside,' Ms Cinit told the paper. 'We thought it was a problem with one of the animals that got loose. Then we were told it was an incident with the wild dogs and that a child had been hurt.'

Uncertainty: A security guard closes the gate to the park, which was temporarily closed immediately after the tragedy

Zoo president and CEO Barbara Baker said staff wrestled with the idea of releasing the calendar, but decided to go ahead as many copies had already made their way into the hands of zoo patrons

In May, 200 patrons were rushed inside buildings and the zoo was put on lock-down when nine of the dogs sneaked out of the exhibit and found its way into a secondary holding pen.



Alone, the dogs, which weigh up to 80 pounds, can be formidable, but in packs they are vicious -- capable of hunting and killing prey many times their size.



They have been known to kill wildebeest and zebras, though they usually pursue less dangerous prey.



The dogs, which are endangered, are among the most deadly predators of the Serengeti Plain.



Their hunts end in a kill 80 per cent of the time. Lions have a success rate of just 30 per cent.



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