Biologists from the University of Bonn have discovered that the cichlid fish Pelvicachromis taeniatus can see in the near infrared range; this was thought to be unlikely until now. Seeing in the infrared range is apparently helping fish to hunt in shallow African rivers. The results will be published in the journal "Naturwissenschaften" and are already available online now.
A research team in the work group of Prof. Dr. T. C. M. Bakker at the Institute for Evolutionary Biology and Ecology, University of Bonn, has been studying the biology of the African cichlid fish Pelvicachromis taeniatus for years.
Researchers conducted a prey choice experiment
Researchers investigated the ability to see in the infrared range using a classical prey choice experiment. P. taeniatus also feeds on small crustaceans, such as freshwater shrimp. These prey animals reflect near infrared radiation. The researchers used this fact to examine the perception of infrared light. In a dark room a prey selection experiment was set up illuminated by infrared lamps. In front of the water basin containing the fish freshwater shrimp were offered in two separate chambers. One of the chambers with the prey was covered with a filter blocking infrared wavelengths. The other chamber was covered with a filter that would let only infrared light pass. "Consequently, the fish were only able to perceive the freshwater shrimp in one chamber in the near infrared range" explains Dr. |Sebastian Baldauf, one of the scientists involved in the study.
Physiologists thought that seeing in the near ir range would be unlikely
The experiment showed that the fish spent more time and were more frequently in front of the chamber that let infrared light pass. "The fish detect their prey based on infrared radiation alone" reports the biologist from the University of Bonn. "Until now, physiologists thought that noise levels in the nea
|Contact: Sebastian A. Baldauf|
University of Bonn