Is The Perfect Pebble The Key To A Prosperous Penguin Partnership?

Down in the frozen beaches of Antarctica, penguins face harsh realities of extreme temperatures, predators, and finding food. But there is still space left over for a little romance. While diamonds might be a little hard to come by, penguin proposals do happen; it just takes the perfect pebble. 

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Gentoo penguins in particular are known to build their nests out of pebbles. The males will choose a nest site and begin building to try and attract a female. If she likes what she sees, the pair will couple up and keep building the nest together. Once the nest is finished, it may be as tall as 20 centimeters (8 inches) and up to 25 centimeters (10 inches) wide. 

The males are also known to scoop up pebbles and carry them to their partner. This not only strengthens their bond but also serves as the starting point for nest building.

While bird species in warmer climes might have all manner of twigs and leaves to choose from, these penguins are pretty limited when it comes to nest-building materials. The penguin parent may line the nest with moss and feathers; however, even just the pebbles help to keep any eggs and hatchlings off the cold ground. Eggs typically hatch in around 35 days, and after another 30 or so days, young penguins will start to form a creche where all the adults look after the young. 

This behavior is even replicated in captivity for Edinburgh Zoo’s gentoo population. “After placing the nests and pebbles in Penguins Rock, it is fantastic to watch the gentoos pick out their favourite stone, find their mate and choose a nest together. It is quite common for gentoos to return to the same nest they have used year after year,” said Dawn Nicoll, Senior Penguin Keeper at RZSS Edinburgh Zoo, in a 2017 statement.

In slightly more cutthroat behavior, both neighboring gentoo and Adélie penguins will even nab pebbles from another's nest to boost their own and decrease the building time. However, the less smooth penguin criminals will often be caught in the act, leading to all manner of squabbling. 

Pebbling has even taken the human world by storm. Instead of bringing your partner or friend a physical pebble, the term has been co-opted for all those reels and memes that you send your mates on social media.