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A team of researchers at the Santa Fe Institute probed humans on Sanak Island and Alaska, and showed that they had historical relationships with local species. They seemed to show that in spite of being "super-generalist" predators, the local hunter-gatherers also collected the food here such that they could contribute to the stabilisation and balance of the ecosystem.

"It's the first highly detailed ecological network data to include humans, which allows us to ask questions about how they compare in their roles to other predators," Jennifer Dunne, who participated in the research, said in a press release."Unlike most ecological studies that ignore humans or consider them as external actors, our analysis includes them as an integral part of the ecosystem."

By hunting marine mammals and fishes for about 7,000 years, the Sanak Aleut hunter-gatherers have left behind a mine of information. Dunne and her team studied the bones and shells they left behind, gathered information about their oral histories from Aleut elders and analysed the ecological data. They collected and collated the local marine food webs that they hunted.

In the intertidal and nearshore food webs, humans hunted a quarter of the species, which was much more than other predators. It was a diet that ranged from primary products such as algae to carnivores such as sea lions at the top of the food chart. They put humans in a special section, just like related "super-generalist predators", such as the Pacific cod.

The Aleuts also shifted their prey like other generalists. When one prey species declined in their population due to the hunting, or because of unfavorable environmental conditions, the Aleuts foraged for alternative food sources. Prey existing in food webs, in which predators "prey-switch" can thus return without getting extinct.

"It's a very stabilizing behavior for the system," Dunne said.

So even though the Aleuts indulged in intensive hunting due to their access to fish hooks, spears and kayaks, they did not face any extinctions.

The findings were published in the Feb. 17 issue of Scientific Reports.