An extreme heatwave in Australia has led to the deaths of more than 90 wild horses in the outback, authorities say.

Rangers found dead and dying animals in a dried-up waterhole near Alice Springs, in the Northern Territory, last week.

About 40 of the animals had already died from dehydration and starvation. Surviving horses were later culled.

It comes amid record-breaking heat, with temperatures hitting 49.5C north of Adelaide in South Australia.

The mercury rose to 47.7C in the city itself on Thursday, breaking a record set in 1939.

How hot is it?
Australia has experienced a fortnight of extreme heat that has broken dozens of records across the nation.

More than 13 towns in the state of South Australia have seen heat records eclipsed.

Emergency services in more than 13 districts are on alert for fear of possible bushfires.

Meanwhile in Alice Springs, near where the horses were found, temperatures have exceeded 42C for almost two weeks - more than 6C above January's typical average, according to Australia's Bureau of Meteorology.

Rangers came across the horses after their absence was noted by a remote community, said local authority Central Land Council (CLC).

A local resident, Ralph Turner, also visited the site and posted photos online, describing the scene as "carnage".

"I was devastated. I'd never seen anything like it - all the bodies," he told the BBC.

"I couldn't believe something like that had happened."

Another local, Rohan Smyth, told the ABC that water was "normally there" and that the horses "just had nowhere to go".

The council said it had organised a cull of the remaining horses because they were found close to death.

They also planned to cull another 120 feral horses, donkeys and camels "dying from thirst" in a neighbouring community, said CLC director David Ross.

"With climate change well and truly upon us, we expect these emergencies to occur with increasing frequency and nobody is truly prepared and resourced to respond to them," Mr Ross wrote in a press release.

Several other wildlife species have also suffered, with reports of mass deaths of native bats in New South Wales.

Up to a million fish have also been found dead along river banks in the drought-affected state.

The government has launched a review into the fish deaths.

How have people been coping?
South Australia health authorities said 44 people had come in for treatment in the space of 24 hours due to the extreme temperatures.

Officials nationwide have issued health warnings urging people to stay indoors and minimise physical activity, with heightened concerns for the elderly, the chronically ill and children.

Earlier this month, officials confirmed that 2018 and 2017 had been Australia's third and fourth hottest years on record respectively.

The bureau's State of the Climate 2018 report said climate change had led to an increase in extreme heat events.

How is climate change affecting Australia?
Even if global temperatures are contained to the Paris accord limit of a 2C rise above pre-industrial levels, scientists believe Australia is facing a dangerous new normal.

Parts of eastern Australia suffered their worst drought in recent history last year, while thousands of Australians fled their homes when bushfires swept through Queensland in November.

The country has committed to reducing its emissions by 26-28% on 2005 levels by 2030, under the Paris climate agreement.

But in November, school students nationwide left class in protest at what they said was a response the government's inadequate action on climate change.

According to the UN's 2018 emissions gap report, Australia's climate policy saw no improvement in 2017, and emission levels for 2030 are projected to be above target.