Penguins to Humans: You’re Seriously Stressing Us Out

King penguins may not be sitting at a keyboard all day, or struggling to pay their bills, but new research shows that they are stressed out all the same.

A study published this month in BMC Ecology analyzed the effects of human contact on a group of King penguins on an island in the Indian Ocean, and found that the penguins were able to tolerate some, but not all, stressors related to human disturbance.

Researchers recorded heart rates in penguins that were regularly disturbed by humans, and compared them to the heart rates of penguins that bred in undisturbed locations on the island. To test levels of stress, they mimicked disturbances by scientists (capture and tagging), tourists (human approach and observance from some distance), and machines (loud noise near their colony).

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All penguins found capture stressful, but those that were regularly exposed to humans were less stressed out by people approaching or by loud noises.

The researchers aren’t sure whether this means that penguins are beginning to acclimate to human meddling; it could be that over time, stress-sensitive birds have abandoned more populous areas, and subsequent breeding has favored the laid-back gene. This, in turn, raises alarms about whether overly calm penguins will be able to cope effectively with serious ecological disturbances like climate change.

One thing is clear: King penguins are affected by humans, and they aren’t alone.

A 2002 study examined Galapagos marine iguanas from a touristy area, as well as iguanas who were undisturbed by humans. The results? Both groups had elevated levels of glucocorticoid steroid hormones, which are typically released during stress (researchers had to capture the iguanas and restrain them for testing), but iguanas from the tourist site had a stress response that lasted longer under identical conditions.

This indicated to researchers that iguanas are physiologically affected by tourism. Research has shown that prolonged stress can lead to chronically elevated glucocorticoid, which has been linked to problems as severe as reproductive failure and neuron death.

Human disturbance is not all bad news: some particularly adaptable species have figured out how to live with the presence of cameras and excitable children. Research on magellanic penguins in South America has shown that glucocorticoid concentrations were lower in penguins living in areas visited by tourists, suggesting that the penguins had been habituated to human contact, and found it less stressful than their undisturbed counterparts. But other studies of threatened killer whale populations have found that exposure to continual boat traffic can result in a significant decrease in the amount of time the whales spend foraging for food, therefore reducing their energy intake.

What about the impacts of scientists? It might seem cruel and unnecessary to capture iguanas and penguins just to measure a hormone. But as humans continue to encroach on natural environments, understanding our effects on wild animals—and how those effects differ from species to species—is an important part of the equation.

Stress and fear responses are not always visible to the naked eye, the penguin researchers point out. Some seemingly calm animals might be undergoing profound chemical or physiological changes as a result of human presence, but it takes scientific study to determine those changes and their significance.

Tourism, too, can be harmful, but it is can also foster stewardship of natural resources: when exposed to wild environments, many people take conservation more seriously, returning home to blog, advocate, and reduce their ecological footprints.

Knowing which species respond well to prolonged human contact can help policy makers regulate human influence over natural environments in ways that are more favorable to native species.

Have you ever vacationed in Antartica? If so, did you interact with wild penguins?