A startling new finding could open up big new possibilities in our understanding of what killed the mammoths.

It still remains unanswered what the cause was: it could have been human hunting, climate change, or both. But new analysis from the University of Michigan could shed some light on the debate, according to a Christian Science Monitor report.

Scientists collected some chemical samples from woolly mammoth tusks from about 40,000 years ago to as recently as 10,000 years ago, toward the end of the last Ice Age. They determined that these mammoths matured much more quickly than earlier versions of the species, which is a good indicator that predation was happening more often, as this is a common evolutionary response — animals that don’t mature quickly spend more time as a vulnerable juvenile and are easy pickings to savvy predators.

The findings aren’t conclusive, but they offer vital new evidence that humans could have played a much bigger role on their extinction than many experts may have realized.

However, there have been studies that indicate that climate change was a big part of the extinction, so it’s certainly not a settled debate.

The scientists at the center of this new analysis offer a hypothesis: climate change likely wasn’t the main cause because it would have caused problems finding food for the mammoths, which should have evolutionarily caused them to wean later, as that’s what happens with elephants. But this new finding indicates that they weaned sooner in order to not be as vulnerable to predators, suggesting that that was the stronger factor.

The research team first observed changes in the chemical structure of nursing and weaning African Elephants at the zoo in Toledo, Ohio. They noted the delay in weaning during drought periods, and looked for that trend in woolly mammoths.

They did that by recording tusk growth, which forms a layer each day and provides insight in the diet and condition of the animal. Using that, they were able to note the change in weaning periods, which seemed to get shorter based on their analysis.