Goldfish can measure the distance they swim in tank: studytext_fields
Goldfish in the tank may not be just swimming in circles there all day. They may well be keeping track of the distance they swim, finds a new study.
Scientists are curious about the mechanism involved in this measurement and wonder if similar brain cells are at work in the internal GPS of the human brain.
Dr Adelaide Sibeaux of the University of Oxford, first of author of the research, said researchers wanted to know where those cells might exist on the evolutionary tree.
A team involving Adelaide Sibeaux and others created a tank with 2cm-wide black and white vertical stripes on the walls. These strips were connected by similar stripes across the floor.
The next they trained nine goldfish to swim along the tank and they would return, when waved at them after travelling 70cm, to their starting position, according to report in The Guardian.
Researchers later tested if the fish could estimate the distance covered and found that each fish made the journey 45 times for each background pattern.
The study reveals that goldfish used an "optic flow mechanism" based on visual density of the environment. In more clear terms, they swam, keeping track of how frequently vertical patterns on the tank's wall changed from black to white. This helped them estimate how far they had travelled.
They must have noticed they were going faster because the world( or striped wall) was moving faster when the width of the stripes were reduced—this made them overestimate how far they had swum.
Researchers also noted that the goldfish could more accurately measure distance when their starting position was closer to the end of the tank.
Also, it is found that some goldfish gauged the distance they travelled based on the number of fin beats they made as they swam.