According to the study, Australia’s giant thunderbirds went extinct 40,000 years ago due to climate change

According to the study, Australia’s giant thunderbirds went extinct 40,000 years ago due to climate change

According to the study, Australia’s giant thunderbirds went extinct 40,000 years ago due to climate change

A new study has suggested that slow breeding patterns associated with a changing climate led to the extinction of Australia’s iconic “thunder bird” over 40,000 years ago.

The research, recently published in the journal The anatomical recordevaluated the large bones of the extinct giant thunder bird or dromornithid, excavated in the northern part of the Flinders Ranges and near Alice Springs in Australia.

Scientists, including those from Flinders University, say that the size and reproductive cycle of these birds have gradually changed over the millennia, but they have failed to keep pace with the climate and environmental changes occurring around them.

“Unfortunately for these fantastic animals, which have already faced the growing challenges of climate change as the interior of Australia became hotter and drier, their reproductive biology and size could not match the faster reproductive cycle of emus. (smaller) moderns to keep pace with these more challenging environmental conditions, ”said Professor Anusuya Chinsamy-Turan, from the University of Cape Town (UCT) in South Africa.

The researchers sought to understand how long it took these giant birds to reach adult size and sexual maturity to determine their evolutionary success and their eventual failure to survive alongside humans.

“We studied thin sections of the fossilized bones of these thunder birds under a microscope so that we could identify the biological signals recorded inside. The microscopic structure of their bones gives us information on how long it took them to reach adult size, when they reached sexual maturity, and we can also tell when the females were ovulating, “said Dr. Chinsamy-Turan.

Scientists have evaluated the bones of the oldest and largest mihirung – the aboriginal name of the bird – Dromornis stirtoni, which lived seven million years ago, was up to 3 m tall and had a mass of up to 600 kg.

They compared it with that of other mihirungs, being the smallest of the flightless birds, Genyornis newtoni – the last species that lived with the first emus.

Based on the research, they say Dromornis stirtoni – arguably the largest bird ever to live on Earth – took a long time – perhaps up to 15 years – to reach its full size and become sexually mature.

Within the next era when Genyornis newtoni experienced, scientists say the climate has become much drier with increasing seasonal variations and unpredictable droughts.

These birds, they say, have grown six times the size of modern emus with a body mass of around 240 kg.

They grew to adult size faster than the first mihirung, “probably within 1-2 years and started breeding soon after,” say the researchers, adding that these birds took several years to reach adult body size. and their growth strategy was still relatively slow.

Scientists claim that the dromorniths were contemporaries of the emu “for a long time” before the final mihirung went extinct.

“The different reproductive strategies displayed by emus and dromornites gave the emu a fundamental advantage when the paths of these birds crossed with humans about 50,000 years ago, with the last of the dromornites becoming extinct about 40,000 years. ago, “study co-author Trevor Worthy of Flinders University said.

While fossil evidence of dromornites suggests that their reproductive biology responded to ever-changing climatic pressures and that they reproduced before their ancestors, the researchers say these birds’ strategy did not come close to the efficiency shown by large birds such as emus living today.

Citing an example, scientists say emus grow to adult size and reproduce within a year or two, a breeding strategy that allows their populations to bounce back when favorable conditions return after periods of drought or food shortages.

“Eventually, the mihirungs lost their evolutionary race and an entire order of birds was lost from Australia and the world,” added Dr Worthy.

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