The penguins are changing the calendar. In an Antarctica that is warming twice as fast as the rest of the world, survival has become a race against time. It is not just the ice that is disappearing: the biological rhythms of these animals themselves are changing.
According to a new study published in Journal of Animal Ecologythe advance of the hot season is forcing entire colonies to distort the moment of mating, bringing it forward by days or even weeks in a desperate attempt to adapt to an ecosystem that they no longer recognize.
The “big brother” of Antarctica. To understand how penguins’ lives are changing, researchers have implemented an unprecedented monitoring operation. Since 2012, a network of 77 high-tech cameras have been installed between the Antarctic Peninsula and nearby islands, monitoring 37 different colonies 24 hours a day. The study, which lasted ten years and focused on three key species (Adélie penguins, Antarctic penguins and Papuans), required four years of data analysis before reaching publication. The result is a frightening snapshot of the changes taking place on the white continent.
Damn spring. The data reveals a shocking climate anomaly: the areas chosen by penguins to nest are warming at an insane rate, around 0.3 °C per year, which is four times faster than the average for the rest of Antarctica (“just” 0.07 °C).
This “early spring” is forcing birds to make a forced choice: bring forward the breeding season. The penguins are trying to synchronize the birth of their young with the new availability of food, but this forced acceleration of biological rhythms puts the delicate balance of the colonies and the future of the species at risk.
Who wins and who loses. The study highlights how the advance of the penguins’ breeding season is record-breaking: the Papuans, for example, have moved the clock back by 13 days on average, with some colonies starting to “work” even 24 days earlier than they did 10 years ago. The Adélie penguins, on the other hand, anticipated the times by “only” 10 days, as did the Antarctic pygoscelids: the three species are therefore, so to speak, reorganizing their respective calendars.
The biggest problem is that not all penguins react to heat the same way. Gentoo penguins eat fish, squid, crabs and other prey that remain relatively abundant even with a warmer Antarctica: the consequence is that, of the three species, they are the only one that is increasing the number of their colonies.
The other two species, which instead specialize in “glacial” prey, have less and less food, and therefore fewer colonies: in their case, the heat coincides with a very rapid decline.
