Early humans may have been more sophisticated and even gutsier than we realized. Researchers examining 4000-year-old trash heaps have identified the genetic remains of several species of whales. The team published their findings in the journal Nature Communications.

The first Greenlanders were the Saqqaq people, who arrived on the frozen continent around 2500 BCE. These were tempestuous times for our planet’s climate and, consequently, for its inhabitants, especially those in extreme habitats. The Saqqaq had to be super-adaptable if they wanted to survive.

Much of what we know about these early Greenlanders has come as a result of picking through their trash. Over the last century, archaeologists have excavated numerous middens (garbage dumps) dating back to the very first Saqqaq settlements. Unsurprisingly, they’ve found a lot of chunks of bone. Bone fragments are super-interesting, but they’re also quite limited in what they can tell us about a given civilization. For one thing, it’s hard to differentiate closely related species by looking at chips of their bones. For another, not every animal skeleton would end up on a trash heap. If the Saqqaq were hunting large animals, it’s unlikely that they would have dragged whole carcasses all the way home.

Fortunately, the middens contained a lot more than just bones.

Researchers collected 34 different sediment samples from settlement sites dating from around 2500 BCE to around 1800 CE. They processed the sediment through a sieve, which left them with piles of midden soil and smaller piles of the parasite eggs that had been living in it. Then they put both dirt and eggs through a battery of DNA tests to identify their origins.

This approach has a number of perks. Genetic testing can pull information from all kinds of organic material, including fat, skin, meat, and claws. And recruiting parasites to the research adds a whole new level of detail, since many parasites are picky and will only feed on certain species. Finding those parasites means there’s a pretty good chance those species were once there, too.

The middens were delightfully diverse in their contents. The researchers found genetic traces of 42 different types of vertebrate animals, including dogs and wolves (which may have been companion animals tethered near the dump), hares, caribou, and seals, and—in the oldest sites—walruses, seals, narwhals, and bowhead whales.

Exactly how the Saqqaq had snagged these massive animals remains to be seen. Whale scavenging was not unheard of in prehistoric times, the authors note, and an unpredictable climate could have caused a surge in whale strandings. But it’s also possible that these prehistoric settlers were out bagging whales. Hunters in other Greenland cultures are known for using poison-tipped spears to immobilize enormous prey; the Saqqaq people may have done something similar.

The discovery that early Greenlanders ate whales is one that “requires re-evaluating maritime history,” the authors write. “Western history has always considered European whaling as the originator and pinnacle of marine exploitation,” yet this study “pushes back the first evidence of whale product usage in the Arctic and can be seen as a logical development of the powers of indigenous observation and ingenuity in the efficient use of a plentiful northern marine energy resource.”

The study is “quite interesting,” says historical ecologist Josh Drew of Columbia University. Drew, who was unaffiliated with the study, recently co-authored a paper on the 19th-century whaling boom’s effect on other species.

The new paper "recognizes the technological acumen of indigenous people,” Drew tells mental_floss, "and shows that they were capable of highly sophisticated hunting techniques (and apparently using biological warfare) to capture whales.”

On top of that, these findings shake up our ideas of a “pristine” baseline for marine ecosystems. “It turns out those populations weren't so pristine,” he says, “and that our species has a long, tangled, history with Arctic marine mammals.”