A pet dog and a venomous snake died after fighting in the backyard of a home in Chatsworth, South Africa, on Saturday.

In a Facebook post, snake rescuer Nick Evans wrote that he received a call from a "distressed" woman who told him there was a snake in her backyard.

"There was apparently a large Mozambique Spitting Cobra in their backyard, and the dog was going at it. I could hear the dog going ballistic, and told her the dog needed to be called away for its own safety," Evans wrote.

He then asked his friend, Duncan Slabbert, to rush to the home as he was closer to the location at the time.

"Unfortunately, in this case, the dog happened to be chained, so the dog couldn't be called or chased away. The dog attacked the snake, and killed it, but in the process, it got spat at and bitten, twice," he wrote.

By the time Slabbert arrived at the home, the dog owner had already rushed the pet to the vet. He found the snake dead at the scene.

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When Evans went to the veterinary clinic, he noticed a "disturbing amount of blood coming out of the dog's mouth."

He spoke to an expert who told him that the snake had hemotoxic venom, which caused the bleeding. The dog also had "extensive bruising around the bite sites."

The owner was informed that the canine must be administered with anti-venom.

"Unfortunately, anti venom and accompanying treatment is very expensive. The dog's condition was deteriorating fast as well. It was decided that euthanasia would be the kindest option," Evans wrote.

Issuing a warning to dog owners, Evans wrote, "If your dog is attacking a snake, without getting between them, please try screaming at them, spray them with a hose, throw water, anything."

Earlier this year, a study conducted by the University of Queensland found that dogs were more vulnerable to snakebites than other household pets due to fast-clotting blood.

A Krabi Pitakpracha Foundation snake handler holds the four-metre (13 feet) king cobra he pulled from a sewer in southern Thailand
Representational image of a king cobra KRABI PITAKPRACHA FOUNDATION / Handout