According to new research, penguins can match their pals’ squawks to their physical appearance – a talent previously unknown in the avian kingdom (except, of course, for crows.)
“Humans have the ability to visualize familiar people by simply hearing their voice,” the study, published this week in Proceedings of the Royal Society B, reminds us.
“This seemingly effortless process, termed cross-modal individual recognition, requires our brain to simultaneously integrate information from different sensory modalities and to identify an individual based on their unique set of multimodal characteristics.”
This ability – integrating various bits of information from all different senses – is a sign of higher-order cognitive function, so figuring out which species can do it is important. Outside of our ever-brainy crow friends, it’s also been demonstrated in lions, goats, horses, and rhesus macaques (who are, in so many ways, the crows of the mammal world.)
Now, we can add penguins to the list – specifically, African penguins. These diminutive birds are native to the coasts of Namibia, South Africa, and (appropriately enough) the Penguin Islands. For reasons that probably aren’t as hilarious as you hope, they are also known as jackass penguins. Living on the beach, surrounded by rocks and wind and ocean, has earned them that title: they’ve evolved to be extremely loud and, for penguins at least, quite gaudy, with each penguin sporting their own unique pattern of spotted markings on their chests.
However, it’s this combination of habit and habitat that has made the penguins so talented – at least, according to study lead author Luigi Baciadonna.
“Imagine a large [penguin] colony in this really challenging environment, with a lot of wind noise, background noise,” he explained to New Scientist. “And potentially, they’re relying on vocal communication, calling to each other as they’re coming back from a hunting trip, for example. But also, their unique pattern of black spots [could become difficult to decipher] amongst the waves and rocks. So the ability to integrate both visual and auditory identifiers can be necessary when one of the cues is not available.”
So how does one go about decoding the higher-order cognitive functions of a penguin? For non-human animals, the study explains, “Evidence for cross-modal individual recognition […] has relied on variations of expectancy violation paradigms.” In other words, you try to confuse the critter.
The scientists took ten penguins from a colony of 17 living at the Zoomarine Marine Park in Torvaianica, Italy, and split them into pairs. Sometimes the pairs would be friends, and sometimes partners – African penguins may be jackasses, but they’re monogamous jackasses. After they had spent a minute together, a keeper came in and ushered one penguin away, leaving the other on their own; about 20 seconds later, a squawk would be heard from behind the door their beau left through.
Presumably unbeknownst to the ‘guins, that squawk was a fraud – one of many pre-recorded penguin calls from other members of the colony. So while the penguins sometimes heard the voice of their partner from behind the door, they sometimes heard the squawk of an entirely different penguin pal.
When that happened, they reacted differently, the researchers discovered. The test penguins responded to every recorded squawk by looking to the door, but they did so more than five times as quickly when the call from behind the door didn’t match the penguin who had just left through it.
“Essentially, if you hear the call from the same guy who just left a few seconds ago, it’s more likely that the call belongs to that guy, not some random [guy],” Baciadonna explained to New Scientist. “So when there’s a mismatch between the visual and acoustic input, we call this a ‘violation of expectation’, and they react more quickly.”
This is an important discovery, providing valuable insights into the evolution of communication and cognition – but it’s not entirely unexpected, according to the researchers. Given the African penguins’ natural territory and behavior, they write, “the ability to identify one's friendly neighbours both visually and vocally may have evolved to help reduce unnecessary conflicts.”
“Penguins … separated from other birds and lost the ability to fly around 65 [million years ago]. They are phylogenetically distant and distinct from most other birds,” concludes the paper. “Our current results suggest that African penguins form internal representations of their colony-mates, suggesting that this ability is much more widespread among the avian taxon than previously thought.”