Gobies are a family of relatively small fish that can change color as protective camouflage. A new study from the University of Sydney has revealed a strange feature of the color changing ability of gobies. The research showed that gobies change their colors more effectively when they are alone rather than with a group.
It costs energy for gobies to change color, and the fish are more vulnerable to predators when they are alone as opposed to when they are in a group. Therefore, it is not surprising that an individual goby would be more likely to invest energy into changing color when threatened.
“Grouping behavior can reduce stress in fish, partly because they are in less danger of attack by predators. This ‘safety in numbers’ effect may allow them to change colour more slowly without added risk,” said PhD candidate and lead researcher Stella Encel.
“Since stress hormones like cortisol and adrenaline are central to the neurological mechanisms of color change in fish, it’s possible that stress levels also directly affect their ability to camouflage.”
This makes sense, considering that people are often comforted by the presence of others. Research shows that this is also the case for other animals as well, such as rats.
For the investigation, the researchers collected goby fish in Australia and took them to a laboratory to be studied. The fish were placed against black or white backgrounds, individually or in pairs, and their color changing response was recorded. A measure of color showed that the color change was finished after about three minutes, and the fish who were alone most closely resembled the color of their background. “Very few studies have examined the role of social context in influencing color change in camouflaging animals, and these have often been done without the benefit of modern colour analysis techniques,” said Encel, “So, not only does our study build knowledge of goby behaviour; it could inform research on the thousands of other camouflaging animals.”
The study is published in the journal Royal Society Open Science.