"We believe that they might, as it seems very useful for the dolphins," said Dr Hanke. ".Captive Guiana dolphins are rare; but they have been kept at the zoo in Muenster, also in Germany.The zoo is among those that have been criticised by animal rights campaigners in recent years, who argue against keeping dolphins in captivity.The researchers became curious about the function of small depressions in the dolphin's rostrum - the forward-projecting part of the head containing the jaws.When one of the animals died, the rostrum was examined, with tissues being stained to show the structures inside these depressions.The depressions - known as crypts - carry whiskers when the dolphins are growing in the womb, but the whiskers later drop off.But the crypts looked as though they were still involved in sensing something.To see whether they were in fact electroreceptors, the researchers turned to the zoo's single remaining.They trained it to put its head on a "rest station", where electrodes delivered a tiny electrical signal into the water.When a signal was present, the dolphin received a reward if it swam away; if not, it received a reward for staying put.Later, a plastic shield was placed above the lines of crypts, blocking any electrical sensing. You will receive a verification email shortly.There was a problem. The pits showed no sign of hair shafts or other features associated with whiskers; instead, they most closely resembled the electroreceptors found in many species of fish and in platypuses. Now, scientists have discovered that at least one dolphin species, the Guiana dolphin, can also detect fish by … "This is a major breakthrough and a beautiful example of convergent evolution where vertebrates at least five times have independently evolved" this ability "by modifying different cell types to serve the same function." "This is a case of convergent evolution," Hanke says. "I think it's possible, it's likely, because there are some dolphins, like the bottlenose, that have little pits on its snout, too. That would be rather like keeping us from using our sense of smell for many years, Hanke says. / Proc. The Guiana dolphin (Sotalia guianensis), also known as the estuarine dolphin or costero, is a dolphin found in the coastal waters to the north and east of South America, and east of Central America.

Hanke and others now say scientists should investigate whether other bottom-feeding cetaceans, such as river dolphins and pygmy sperm whales, share the ability.

male Guiana dolphin determined a sensory detection threshold for weak electric fields of 4.6 |j.V cm-1, which is comparable to the sensitivity of electroreceptors in platypuses.
",That skepticism has given way to full-blown praise, says Peter Teglberg Madsen, a sensory biologist at Aarhus University in Denmark.

"If this holds up, it will be exciting to do follow-up work.

But infrared photographs of the pits, called "vibrissal crypts," showed them lighting up with activity, Hanke says, "so we knew they must have some function.
Hanke suspects the gel helps conduct the electrical signals.After discovering the electroreceptors in the deceased Guiana dolphin, the researchers then tested the other dolphin, named Paco, to see if he would react to a weak electrical signal like that generated by small- to medium-sized fish, his natural prey. The dolphins' cells also contained a gel-like substance, similar to a gel found in the receptors of fish and a mucus in those of the platypus. It is a member of the oceanic dolphin family (Delphinidae). New York,

It is the first time this sense has been reported in a marine mammal—or in any placental mammal. Moreover, Madsen says, there's a lesson in Hanke's findings: "It emphasizes that we need to be open to the fact that animals gather information in ways that are very different from those of humans. (Image: © Wikimedia commons user Archilider).These are the electric field sensing receptors on the Guiana dolphin. B / A. Liebschner).Receive news and offers from our other brands?Receive mail from us on behalf of our trusted partners or sponsors?Gallery: Evolution's Most Extreme Mammals,These could be the funniest animal pictures ever,Facial reconstruction reveals Egyptian 'mummy portrait' was accurate except for one detail.What did people use before toilet paper was invented. They tested different strengths of fields; the animal sensed the field correctly most of the time at a very low level — 5 microvolts per centimeter — lower than the level produced by a typical electric fish.No other "true" placental mammal is known to have developed the ability to sense electric fields. Nicole Czech-Damal from the University of Hamburg discovered this amazing ability by studying the Guiana dolphin, also known as … They use this sense in combination with their ability to echolocate, when they are too close to their target to detect an echo. The threshold was determined close to 4.6 µV by extrapolating the percentage of positive and negative … Until this discovery, it was known only in fish, amphibians, and two egg-laying mammals, or monotremes, the platypus and echidna.All animals generate weak electric fields from the activity of their muscles and nerves. At some point in the dolphins' evolutionary past, an ancestor had whiskers sprouting from these pits, and most researchers thought they no longer served a purpose. The researchers expect that electroreception, as this sense is called, will be found in other cetacean species. "All of the dolphins' prey items, like crayfish, all of them,The Guiana dolphin looks like the familiar bottlenose dolphin; it is only slightly smaller. Psychophysical experiments with a male Guiana dolphin determined a sensory detection threshold for weak electric fields of 4.6 µV cm −1, which is comparable to the sensitivity of electroreceptors in platypuses. The Guiana dolphin (Sotalia guianensis) lives around the east coast of South America, and resembles the much more common bottlenose variety. R. Soc. "Most of the animals which do this do this to find prey," said study researcher Wolf Hanke, of Rostock University in Rostock, Germany. Dolphins are famous for their ability to hunt prey via echolocation. When he did not detect a signal, he remained in the station.The scientists conducted 186 trials, presenting the dolphin with a range of electrical signals from low to high.