Researchers have found that the waterfall-climbing fishes utilize the same set of muscles for climbing and eating.
This research has been published online in the journal PLoS ONE.
The Nopili rock-climbing goby has the ability to climb up the waterfalls as high as 100 meters. Theses fishes use combination of two suckers to climb and one of these suckers is also used to eat algae.
In this study, researchers have found, after filming the fishes, that the fish’s overall movements during climbing and feeding are almost the same. Scientists are not clear whether feeding movements were developed for climbing or vice versa but the same muscles are utilized for two very different needs.
Researchers wrote, “Although current data cannot resolve whether oral movements for climbing were coopted from feeding, or feeding movements coopted from climbing, similarities between feeding and climbing kinematics in S. stimpsoni are consistent with evidence of exaptation, with modifications, between these behaviors. Such comparisons can provide insight into the evolutionary mechanisms facilitating exploitation of extreme habitats.”
“We found it fascinating that this extreme behavior of these fish, climbing waterfalls with their mouth, might have been coopted through evolution from a more basic behavior like feeding. The first step in testing this was to measure whether the two behaviors really were as similar as they looked” Blob, lead author on the study, said in a statement.
This research shows that if you stop the fishes from climbing the waterfall, it is quite possible that they would die of starvation.
Cullen, J., Maie, T., Schoenfuss, H., & Blob, R. (2013). Evolutionary Novelty versus Exaptation: Oral Kinematics in Feeding versus Climbing in the Waterfall-Climbing Hawaiian Goby Sicyopterus stimpsoni PLoS ONE, 8 (1) DOI: 10.1371/journal.pone.0053274