Crows use mirrors to hunt for food
Crows join the short list of animals known to be capable of processing information from mirrors.
Wed, Sep 21, 2011 at 03:09 AM
Crows are known for being wily animals capable of using tools. Now scientists from the University of Auckland, New Zealand, have proven that they may also belong to an exclusive club of intelligent creatures that can process information from mirrors and reflections, according to the BBC.
The list of creatures currently known to process mirror information reads like an encyclopedic entry on animal intelligence: humans, great apes, dolphins, monkeys, elephants and African grey parrots. Crows are joining an elite group.
The study was performed on 10 wild-caught New Caledonian crows that were housed in large mirrored cages. The mirrors were placed in a way that reflected the location of hidden cubes of meat, which were otherwise concealed from sight. Amazingly, all 10 of the birds appeared to easily navigate the mirrored funhouse and quickly find the meat.
"We were surprised by how quickly the crows learnt to use a mirror reflection to locate hidden food," said Felipe S. Medina Rodriguez, lead researcher on the study. "Usually, it takes longer for an animal to start using the properties of mirrors to have access to otherwise non-visible objects."
Researchers were able to rule out the possibility that the crows were using some other method for locating the meat — such as their sense of smell — by turning the mirrors over, thus removing the reflection. When the mirrors were reversed, the crows failed to locate the food.
That crows were able to quickly utilize the mirrors is particularly impressive since they were all wild birds. Previously these kinds of studies have been practiced on animals held for some time in captivity, leaving open the possibility that they picked up the skill only after extensive interaction with humans. This study demonstrates that these crows likely developed their mirror-using skills in the wild.
"What our study has now revealed is that wild-caught New Caledonian crows can process mirror information in a primate-like fashion, and that this ability develops very quickly without extensive mirror exposure," Rodriguez noted.
The crows showed great mental dexterity in navigating their mirrored cages, but researchers did note that they failed in another important mirror test: the mirror-recognition test. None of the 10 birds seemed to identify their reflection as their own. All the crows reacted to seeing their reflections as if they were encountering another crow, often raising their tails or attacking the reflection. Some of them even peered around the corner of the mirror hoping to catch a glimpse of their "rival."
Even so, the crows' mirror use is impressive, and the development of this ability in the wild demonstrates a natural disposition for the task.