Australia's rabbit population has been a topic of interest for many years, especially when it comes to its history and impact on the environment. In the 1920s, Australia's rabbit population reached an astonishing 10 billion, but today, it's estimated to be around 600 million.

Despite their impressive reproductive ability, it's believed that if 10 billion rabbits were transported to the Jurassic period, they wouldn't have a significant impact on the ecosystem. Let's delve into the reasons why.

A Clean Slate: Australia's Unique Biology

Australia was once a blank slate, biologically speaking. Separated from other continents for millions of years, it had its own unique flora and fauna, including marsupial mammals.

In 1859, a British named Thomas Austin introduced 17 rabbits to Australia, kept them in cages, and eventually released them on his farm for hunting.

However, within just six years, the farm was overrun by tens of thousands of rabbits that had escaped and gone feral. By the end of the 19th century, there were at least 30 million rabbits in Australia.

Challenges in the Jurassic Period

Despite their impressive reproductive abilities, it's unlikely that 10 billion rabbits would thrive in the Jurassic period. Here are three reasons why:

Oxygen: All existing rabbits belong to the order Haremalia, but they did not evolve in the same environment as dinosaurs. The Jurassic period had relatively little vegetation due to volcanic eruptions and geological movements, leading to a low-oxygen environment with only 68% of the oxygen levels present today.

Temperature: European rabbits, native to the northern temperate zone with cold winters, have thick and long fur. However, the Jurassic period was much warmer, with an average temperature of 3°C higher than even today's tropical regions. This high temperature would be fatal for these thick-furred rabbits.

Survival environment: The Jurassic period was dominated by large forests while burrowing rabbits preferred open grasslands. The landscape of the Jurassic period would not have been suitable for the survival of rabbits.

This is because the conditions of the Jurassic period were vastly different from those of the present day. The atmosphere had only 68% of the oxygen it has now, and the temperature was 3°C higher than today's tropical regions.

Additionally, the landscape was dominated by large forests, which were not suitable for the burrowing rabbits, which are native to Europe and prefer open grasslands.

Given the low oxygen levels, high temperatures, and unfavorable landscape of the Jurassic period, it is unlikely that the introduction of these rabbits would have been successful.

They would have struggled to survive in such conditions and would not have become a dominant species as they did in Australia.

In conclusion, the idea of placing Australia's 10 billion rabbits into the Jurassic period is an interesting thought experiment, but it would not have had a significant impact on the ecological balance.

The conditions of the Jurassic period were not conducive to the survival of these rabbits, and they would have struggled to thrive in such an environment.