Giant Carnivorous Ants Swarmed North America 47 Million Years Ago, Raising Questions on Prehistoric Insect Size

Giant carnivorous ants flooded the ancient forest floors of North America, searching for food more than 47 million years ago. In today's standard, the word giant might be an exaggeration. However, the ancient ant queen of this species was as big as hummingbirds that governed ant colonies in what is now Wyoming.

Are Those the Largest Ant Queen Fossil?

Science Alert reports that scientists from Simon Fraser University (SFU) said their findings on the newest fossil discovery in Princeton, B.C. is, generating concerns about how animals and plants dispersed over the Northern Hemisphere millions of years ago, including whether brief periods of global warming were involved.

But the recently discovered ant fossil is still not the largest ant that ever walked on Earth. Its relative found in Germany was the biggest known ant queen ever to exist. The fossil was estimated to possess a body mass of a wren that is over 5 cm (2 inches) long and had 16-centimeter-wide wings. The ant workers hunted anything in their path, like reptiles, animals, and birds.

These ancient insects, like contemporary ants, were most likely ectothermic. Being ectothermic means they probably struggled to exist without a significant quantity of heat in their habitat. Their body size determines how low the temperature can go before they die.

While animals that can regulate their temperatures may tolerate colder weather by increasing their bulk and decreasing their skin, animals that must absorb heat from their surroundings benefit from increased surface area and less volume. Larger ant queens, for example, can now be found closer to the tropics.

The new fossilized ant was found by Princeton resident Beverley Burlingame who gave it to the town's museum. Researchers said that it is the first specimen of the extinct ant Titanomyrma found in Canada.

SFU paleontologist Bruce Archibald said that the ant and its relative are close in age to other Titanomyrma fossils long known in Europe, particularly in England and Germany. Due to that, it raised some questions about ancient migratory patterns of insects in the Arctic region.

How Does Insect Size Influences Migration?

In the past, Europe and North America were connected by land across the Arctic. On the other hand, there were some questions about whether the climate was suitable for migration at that time.

Scientists discovered that ancient climates were hot where ants lived in Wyoming and Europe, EurekAlert! reports. More so, they found that modern ants with the largest queens live in hot climates, which led scientists to link the ant queen size to high temperatures. However, this creates a problem, as a milder climate in the Arctic would still not have been hot enough for Titanomyrma to pass.

In 2011, the same researchers suggested in their previous study that this might be due to geologically brief intervals of global warming when these ants existed. They predicted that the ant would not be found in temperate Canada as it would have been a lot cooler.

When the new Canadian fossil was warped by geological pressure during fossilization, its real-life size could not be determined. It might have been as enormous as some of the largest Titanomyrma queens, or it could have been smaller.

Archibald noted that the fossil is helping scientists understand how ancient plants and animals lived when the climate was much different. Understanding ancient Arctic migration explains animal distribution today.