We’ve all had the “this could use a sauce” moment. Whether it’s bread, a chip, or something else, we’ve all dipped dry food into some sauce to make it tastier. Apparently, cockatoos do it too. When provided the option, they use soy yogurt to flavor their food, providing compelling evidence of cognitive sophistication beyond mere instinctual foraging.
In the 1960s, researchers in Japan found that macaques would dip potatoes in saltwater. They would also dip them in fresh water, but when given the choice, they would prefer saltiness because it made the potatoes taste better.
Since then, dunking food in liquid before consumption has been observed in several animal species, but none as sophisticated as the macaques. Most accounts are anecdotal, but there seem to be several reasons why animals do it:
- Soaking – Softening hard or dry food.
- Cleaning – Removing dirt or undesirable substances.
- Flavoring – Enhancing the taste of food.
- Drowning prey – Subduing live food.
- Transporting liquid – Using food as a sponge to carry liquid.
Most cases of dunking behavior have been anecdotal, making it difficult to ascertain the exact function. The Goffin’s cockatoos, however, displayed a novel and experimentally confirmed food flavoring behavior, previously only documented in Japanese macaques. So, a team of researchers decided to look deeper into that.
Blueberry yoghurt for me, please
The study started in November 2022 when researchers noticed two cockatoos, Irene and Renki, dunking cooked potato pieces into blueberry-flavored soy yogurt during breakfast. This prompted a series of controlled experiments to determine the function of this behavior.
“Continuing our previous dunking observations, 13 we investigated the function and frequency of this behavior. Therefore, we conducted 14 additional breakfast observations (30 min each), in which we presented the group of cockatoos with a food bowl and three potential dunking mediums: (1) fresh water, (2) blueberry-flavored soy yogurt, and (3) neutral soy yogurt, which acted as an unflavored texture control,” write study authors Jeroen Stephan Zewald and Alice Marie Isabel Auersperg, from the University of Veterinary Medicine Vienna.
The researchers extended the test to 18 cockatoos. A total of 9 out of 18 birds engaged in dunking behavior, predominantly using the blueberry yogurt. The cockatoos never dunked their food in water, ruling out soaking or cleaning as possible explanations. Blueberry-flavored yogurt was chosen more often than neutral yogurt, even though both had the same texture. The birds were vigorous in their dunking, dragging the food in yogurt to absorb as much as possible.
Carrots and cauliflower were never dunked, and rarely eaten — the cockatoos didn’t seem to enjoy them so much. Noodles and potatoes were popular, however. Noodles (fusilli) were dunked more frequently than potatoes. Because they are also more absorbent than potatoes, the researchers believe this is a preference for foods that could better absorb yogurt.
The birds also showed a higher probability of eating dunked food than eating yogurt alone, further confirming that the combination, rather than just the yogurt, was desirable.
Smart birds
The observed behavior suggests advanced cognitive abilities in Goffin’s cockatoos. Previous research has shown that these birds exhibit tool use, problem-solving, and even sequential reasoning, similar to primates. This study adds another layer of depth to their cognitive ability, indicating an ability to experiment with food combinations.
But this is where it gets even more interesting.
The fact that only 9 out of 18 cockatoos exhibited this behavior suggests that it is an innovation rather than an instinctive behavior. Interestingly, only two individuals, Kiwi and Moneypenny, demonstrated dunking behavior in both this study and a previous study on rusk-soaking. These birds also used a different dunking technique, more similar to soaking, suggesting a potential cognitive pathway leading to innovation.
But why do the birds do it? Researchers suspect this is simply due to taste optimization: in other words, they like the flavor that yogurt brings. Another option is that this is merely a way to eat more food and improve caloric intake. For Goffin’s cockatoos, which are generalist feeders consuming fruits, seeds, and roots, experimenting with new food sources may provide an adaptive advantage.
“They ate the food and yogurt together and never licked the yogurt off before eating the food, indicating their preference for the combination of both food items,” the researchers write in the study.
At any rate, the fact that cockatoos do this in the first place is surprising enough. It shows advanced cognitive abilities that were previously considered to be unique to primates.
Future research could investigate whether other highly intelligent bird species, such as crows or African grey parrots, exhibit similar behaviors. However, researchers don’t recommend testing this out at home.
The study was published in Current Biology.
