Monkeys make tools. Birds build houses. And ants grow agriculture.

Bees live in complex societies, and many creatures use basic language to communicate.

It could be argued that the biggest differentiator of humans from other animals is that we have harnessed energy—first and still foremost in the form of fire.

Fire kept us warm, allowing early humans and our ancestors to spread into harsher climates. It helped us hunt, then gave us the ability to cook. We gathered around the fire at night, which helped us develop language, share stories and build cultures and religion.

Scientists have theorized that fire was so instrumental to human development, we could not have evolved without it.

Cooking with fire broke down tough animal protein and plant matter, making things that may not have been edible now digestible and more nutritious.

This may have given prehumans the calorie and protein surplus to develop bigger brains, to build stronger communities, to spend more time raising children and passing knowledge to them.

Scientists have found evidence of hearths, places to cook and gather, from as far back as one million years ago.

Four-hundred thousand years ago, hominids may have realized they could strike flints to make sparks, which made fire portable.

And today, three billion people still get most of their energy from burning wood and biomass.

Humans make fire, but fire also made humans.