What was Earth like in the age of giant insects?

More than 300 million years ago, before the age of giant dinosaurs, Earth was home to giant insects.

The Carboniferous Period was one of the most transformative times in Earth's history. The planet's landmasses were beginning to form into the supercontinent Pangaea. Vast swamps and warm, wet forests dominated the landscape. And giant insects weren't the only giant creatures roaming the planet. There were also plenty of sea creatures, like the first forms of sharks and a giant amphibian.

Now, the first thing you'll notice are the giant insect-like creatures. One of the most iconic is the meganeura . This insect resembles the modern dragonfly, except for one big difference. It had a wingspan of up to 75cm. Even scarier, it was a carnivore, preying on other insects and small amphibians.

There was a time in our planet's ancient history when Earth was home to some of the most incredible creatures imaginable. This was an age of giant insects, when dragonflies had wingspans as long as eagles and millipedes were longer than a human arm. Comparing the giant insects of the past with modern insects reveals the incredible changes in Earth's ecosystems over millions of years.

Another scary-looking insect is the pulmonoscorpius . This is a giant scorpion that mainly roams the swampy areas of the Earth. They can grow up to 70 cm long. There are also giant cockroaches that grow up to 10 cm long and mayflies with a wingspan of 45 cm.

So it's safe to say that you'll have a lot to look out for as you wander the Earth during this period. But the question is, how did these insects get so big?

Research has estimated that atmospheric oxygen levels were as high as 35% during this period. Oxygen was one of the main factors that caused the giant insects of the time. But why did this make them so huge?

Carboniferous Period, about 359 to 299 million years ago. The world was very different from what we know today, with lush forests and much higher levels of oxygen in the atmosphere, making it an ideal place for giant insects to thrive. These giant insects are a testament to the incredible diversity and adaptation that life on Earth has undergone throughout its history.

Insects breathe differently than other creatures . Insects don't have a circulatory system to transport oxygen, instead it is delivered directly to their tissues through a network of tiny tubes called tracheae. The more oxygen in the atmosphere, the larger these insects become. But there may be more reasons why insects grow to this size. Another theory is that these insects are forced to grow so large due to oxygen poisoning.

Too much oxygen in the body can create something called 'free radicals .' These are unstable molecules that can damage cells and even your DNA. In the case of insects, they are forced to grow to enormous sizes to avoid oxygen poisoning.

Growing larger will slow down the rate of oxygen absorption. As for humans, living in such a high oxygen concentration environment will cause nausea, respiratory problems and even some effects on the nervous system.

Scientists believe that high oxygen levels, the absence of large predatory vertebrates, and evolutionary adaptations all contributed to insect giantism during this time.

During the Carboniferous period, oxygen levels were around 35% higher than they are today. This abundance of oxygen was crucial to supporting the enormous size of insects, as it allowed them to oxygenate their bodies efficiently. Fossil remains of these giant insects have been discovered in many places around the world, providing valuable insights into Earth's ancient past.

Carboniferous forests were dominated by towering tree-like plants such as ferns and horsetails. These plants provided abundant food for giant insects and contributed to the overall biodiversity of the era.

As Earth's climate and vegetation changed and as larger vertebrate predators evolved, the age of giant insects gradually ended. Smaller, more agile insects eventually took over.

One of the most iconic creatures of this era was the Meganeura, a dragonfly with a wingspan of up to 2.5 feet (76 cm).

The Giant Millipede Arthropleura, a species of giant centipede, can grow to over 2 metres long. Despite their terrifying size, they are herbivores and pose no threat to humans.