The story says: The fish's memory is only 7 seconds, and when it turns around, it forgets the scenery behind it. Even the smallest fish tank is also a vast world of fish, and there is always a novel space worth exploring.
The story makes up a beautiful lie for you, so that you have no guilt and calmly imprison the fish in the fish tank. However, this lie is so wrong that a fish with only 7 seconds of memory may not live more than 7 seconds.
Contrary to lies, fish have very good memories, both short-term and long-term, and they remember where to go to find food, remember the dangers they have experienced, and remember the way home.
From goldfish kept in captivity in aquariums, to rainbow fish in inland streams, to gobies in the ocean, fish that live in different environments have equally outstanding memories.
<h1>Goldfish in the aquarium</h1>
Students at the University of British Columbia in Canada conducted course experiments on the color vision resolution of the common goldfish (Carassius auratus). The students borrowed a batch of ornamental goldfish from the aquarium, and each goldfish was assigned a straw of a different color, which was fed daily with a special colored straw for the goldfish. Experiments have found that goldfish have a keen color vision resolution. After a few days of feeding, each goldfish recognized the color of its own special straw, and when the feeding straw reached into the fish tank, the horse swam to its own straw to wait for food, which was accurate.
After the course experiment, the school of goldfish is sent back to the aquarium. The following year, the students did another study of animal behavior and borrowed goldfish from the aquarium. This batch of goldfish includes old goldfish who participated in color vision experiments last year, and some new goldfish. When the colored straws of the feeding reached into the fish tank, last year's old goldfish horses swam to the straws of their own special color, waiting to be fed, and none of the goldfish ran in the wrong place. After a year, the goldfish still remember the straw that was previously fed, and the average life expectancy of the captive goldfish is only 6 or 7 years.
Are you going to test your memory with a goldfish? Imagine, do you remember the color of the chopsticks used for eating at this time last year?
Compared with the captive goldfish that live safely and drink without worry, the observation and memory of fish living in the wild are stronger, let's first look at the memory of freshwater fish. [Headlines - France is Bacon - Please do not reprint other platforms without authorization]
<h1>Rainbow fish in the stream</h1>
A team from the University of Queensland in Australia caught a flock of Melanotaenia duboulayi in a nearby stream, which also has a nice name called rainbow fish. Rainbow fish with a red dot at the corner of its eye and an average length of only 5 cm, is an indigenous freshwater fish living in Australia.
The team specially made a 200×30×30 cm fish tank, pulling a large net in the middle of the fish tank, and the fishing net was close to the edge of the fish tank, leaving no gap, only digging a hole with a diameter of 2 cm in the middle of the net. The net initially stays on the far right of the tank, and when the rainbow fish is placed in the tank, the net begins to move at a uniform speed from the right to the left, and it takes 30 seconds to move to a trip. The net runs to a stop 3 cm from the left end and holds for 60 seconds. If the Rainbow Fish can't find an escape hole in this 90-second period of time, it fails and the experiment starts again.
The team divided the rainbow fish into 5 groups, and each group of fish was tested five times for net catching. In the first experiment, the fish panicked, and most of them were trapped in a corner of the fish tank by the net and could not escape. Of the 10 groups of fish, only two of the only fish in the group found holes in the nets and managed to escape. After the experiment continued several times, the success rate of the fish escaping from the net increased significantly, and when a companion was seen escaping from the net hole, the remaining fish would follow the successful person and swim out of the net hole. By the 5th time of the experiment, all the rainbow fish were able to escape in 90 seconds.
The more times the experiment is repeated, the shorter the time for the fish to escape from the net. In the first 5 experiments, the average escape time of the fish was 74 seconds, and by the next 5 experiments, the escape time of the fish was reduced to 47 seconds.
The net could no longer trap the rainbow fish, and each fish remembered the hole in the middle of the net. The test wasn't over yet, and after 11 months, the rainbow fish was once again put into the experimental fish tank. At this time, the rainbow fish that saw the mobile net again behaved very calmly, and found the hole in the fishing net in the first test, and successfully escaped from the fishing net. The Rainbow Fish fled at the same speed as it had 11 months ago, and the memory of that dangerous experience was intact.
It's astounding: Rainbow fish have a lifespan of only 3 years, and they remember their experiences from 11 months ago, which accounts for one-third of the length of their lives.
Are you going to test your memory with a rainbow fish? Imagine getting lost on the streets of a different place 30 years ago, and after a few detours, you finally found the right passage. Now that you are allowed to return to your hometown and walk again, can you go the right path for the first time?
The memory test of the rainbow fish is over, and then we look at the observation and memory of the marine fish.
<h1>Gobies in the ocean</h1>
The bathygobius soporator is an inconspicuous fish by the sea, with an average length of only 7.5 centimeters, and it is found on both the Atlantic and Pacific coasts. The earth-brown ruffled-fin goby has eyes that grow on the top of its head and is draped with a folded dorsal and caudal fins. Its left and right ventral fins come together to form a suction cup that, when the big wave comes, is able to adsorb its body onto the reef without being washed away.
Finger-long gobys feed on small worms and shrimp and crabs, and in the reef pits on the shore where the tide recedes, they gather gobies for a delicious meal. At low tide, gobies often roam in reef pits with shallow waters. Octopuses in the sea and herons on land also know that reef pits are a good place for food to gather, and when they have time, they come to scavenging, and gobies have become the biggest harvest for hunters.
The goby stuck in the reef pit is not willing to be caught, it has developed a bouncing skill, can jump from one reef pit to another to avoid danger. What's even more exciting is that the gobies don't just jump once, the reef pit next to it is just a stop, and it will jump from stop to station until it reaches the ocean. The most amazing thing is that the goby trapped in the reef pit can't see the surrounding environment at all, but can always jump into the nearby pit accurately and not land on the rock.
Back in 1950, Lester Aronson, a biologist at the American Museum of Natural History, discovered the gobies' bouncing escape stunt. He observed several cases of gobies escaping on Bimini Island near the museum.
The picture above is Aronson's schematic diagram based on the actual situation, 3 gobies initially stayed in the starting reef pit in the lower left corner, and began to escape under the disturbance of artificially stirring up the water with wooden sticks, and 1 of them followed the indicated route, swam through shallow water, crossed the ravine, jumped over the reef, and successfully reached the ocean in the upper right corner. The widths of the gobies-jumping barricades are as follows:
1, B2→C1,6 cm; 2, C2→D1,5 cm; 3, D2→E, 30 cm; 4, E→ F, 15 cm; 5, F→ G, 38 cm; 6, G→H, 35 cm.
Along the way, the gobies have jumped over 6 obstacles of varying widths and narrows, crossed a winding road of 9.5 meters from the starting reef pit to the mouth of the sea, and successfully returned to their homeland.
The picture above is a picture of the actual terrain of the reef group, the way home for the goby is not a straight line, the size of the reef pit is different, the width of the obstacles crossed during the jump is different, and the direction of each jump is also different. In such a complex terrain, 2 of the 3 gobies were exhausted and stopped in the middle of the road, and 1 successfully escaped. In other relatively simple terrains, gobies have a higher escape rate.
How can gobies that can't see their surroundings know the direction of the ocean, the exact location of the reef craters on the way? Aronson brought the gobies from the ocean back to the lab, where artificial reefs were built, pits of varying sizes and shades were dug, and the rise and fall of the sea was simulated.
The picture above is a schematic diagram of an artificial reef pit in a fish tank, the top of which is a large deep puddle, and below there are three small shallow puddles A, B and C, surrounded by dry cement. When the tide is high, the sea floods all the pits and the ground, and the goby are able to roam everywhere. When the tide falls, the four reef craters are independent and do not communicate with each other.
In the first experiment, when the tide was low, the goby was put into the A pit and stirred the water with a stick, and the goby panicked, but could not jump. Then poke the goby with a stick, and the goby is forced to be helpless and can only take off, with an 85% probability of jumping to the cement floor.
In the second experiment, at high tide, the goby was put into the fish tank. Then drain the water to simulate the falling tide, after the low tide some goby stay in pit A, then use a stick to stir the water, goby jump, jump to pit C (goby will not jump to the next pit B, but directly choose pit C). Then stir the water in pit C, the goby takes off and jumps to the deep puddle, and the success rate of the goby finally jumping to pit C is as high as 97%.
After 40 days, the first experiment was repeated again, and the goby put into pit A still remembered the previous escape route and successfully returned to the deep puddle.
The secret of the goby's home is revealed, and it remembers the location and depth of the surrounding reef pits at high tide, and can enter the pit correctly when fleeing for its life. What's even more powerful is that as long as it walks through it, the goby will remember the way home, and the interval of 40 days will not be wrong.
Are you going to test your memory with gobies? Imagine if you were blindfolded at the door of the community, can you walk home smoothly? Don't bump into trees and flowers on the side of the road, trash cans in the corners of the wall along the way.
From aquariums where they can eat and drink to reefs that are in danger, ordinary little fish have proven their excellent observation and memory time and time again. The finger-long fish, the brain is only the size of a soybean, and the information loaded inside has far exceeded our imagination.
Every life should not be underestimated, this article debunks the rumor: the memory of the fish is only 7 seconds.
#这很科学 #
Resources:
1：“Differences in timidity and escape responses between predator-naive and predator-sympatric rainbowfish populations”，https://researchers.mq.edu.au/en/publications/differences-in-timidity-and-escape-responses-between-predator-nai
2：“Social mechanisms enhance escape responses in shoals of rainbowfish, Melanotaenia duboulayi ”，https://animalstudiesrepository.org/acwp_aff/19/
3：Fish Behavior in the Aquarium and in the Wild
4：“A Comparison of Spatial Learning and Memory Capabilities in Intertidal Gobies”，https://animalstudiesrepository.org/cgi/viewcontent.cgi?article=1094&context=acwp_asie
5：“Orientation and jumping behavior in the Gobiid fish Bathygobius Soporator”, http://digitallibrary.amnh.org/bitstream/handle/2246/3993//v2/dspace/ingest/pdfSource/nov/N1486.pdf?sequence=1&isAllowed=y
6: “Spacial Mapping in a Jumping Fish The Frillfin Goby Bathygobius soporator”, http://ncf.sobek.ufl.edu/NCFE003709/00001
7: “Further studies on orientation and jumping behavior in the Gobiid fish”, https://nyaspubs.onlinelibrary.wiley.com/doi/abs/10.1111/j.1749-6632.1971.tb13110.x
8: Image source: Wikipedia
P.S. Today we are updating the secrets of nature series, which is the 4th article: The Memory of Fish.