accepted
The key to the work is the CymaScope - a new instrument that reveals detailed structures within sounds, allowing their architecture to be studied pictorially. Using high definition audio recordings of dolphins, the research team, headed by English acoustics engineer, John Stuart Reid, and Florida-based dolphin researcher, Jack Kassewitz, has been able to image - for the first time - the imprint that a dolphin sound makes in water. 
The bufeo colorado, pink dolphin (Inia geoffrensis), is considered a powerful shaman, which casts spells when it surfaces, perhaps because its blowhole makes blowing and whistling sounds similar to those made by a shaman. Much dolphin behavior supports belief in their intelligence. They are curious, and they will swim near boats and approach swimmers in the water. They will chase a school of fish, allowing fishermen to go upstream and set their nets; the dolphins will then remain on the outside of the nets, easily capturing any fish that escape — a curiously symbiotic relation between humans and dolphins.
Mestizos firmly believe that dolphins seek sexual intercourse with human beings. A menstruating women in a boat is in particular danger; a dolphin will ram her boat and overturn it, dragging her to the river bottom for sexual intercourse, where the woman may drown. Dolphins also turn into human form in order to seduce women and to make children that will later serve them. They appear primarily as fair handsome men dressed in dapper white linen suits and Italian fedoras, who attend parties, buying drinks for everyone, and stealing or seducing women amid the noise, confusion, and dancing. An infatuated woman may disappear, having thrown herself into the river out of her desire to stay forever with her dolphin lover. Thus, too, if a young woman is impregnated and the father is unknown, the pregnancy is often blamed on a nocturnal liaison with a dolphin, who presumably lured the maiden into the water.
But, just as chullachaquis cannot hide their deformed foot, dolphins cannot disguise their blowhole, and always appear wearing a hat; and they will not drink, since being drunk may break the spell and reveal their true identity. Such an interloper may be frightened away by removing his hat and revealing that he is really a dolphin.
In line with the attributed sexuality of the dolphin is the belief that female dolphin genitals are the same as — indeed, more desirable than — those of human females. It is said that no woman can compare with a female dolphin in the passion or skills of sex. Stories are told of men who began to copulate with female dolphins, and found it so pleasurable they could not stop, until first their semen and then their blood was completely drained. Don Agustin Rivas tells how, when he was thirteen years old, he in fact had sex with a dolphin that had jumped into his boat — a dolphin, he says, “with small breasts and pubic hair just like a woman.” He thought the dolphin had jumped into his boat in order to have sex with him; he had heard “that dolphins could be more sexually gratifying than women,” so he took off his pants and had sex with it.
Dolphins are not hunted for food, but for body parts. If a man wears the ear of a dolphin on his wrist, he will enjoy large and lasting erections; the vulva of a dolphin tied on the upper arm makes one irresistible to women; hanging a dolphin tooth around the neck of a child will cure diarrhea; a powder made from the pulverized eye, fat, teeth, or penis of the dolphin may be used to seduce women. A sorcerer can attack a woman using the penis of a dolphin, calling the spirit of the dolphin to inflict on the woman a voracious sexual appetite, which she then alleviates with every available man. The slaughter of river dolphins for these purposes may be endangering the species.
The sexual reputation of dolphins is not entirely unearned. Take a look at this:
Scientists have taught dolphins to combine both rhythm and vocalisations to produce music, resulting in an extremely high-pitched, short version of the Batman theme song.
The findings, outlined in two studies, are the first time that nonhuman mammals have demonstrated they can recognise rhythms and reproduce them vocally.
"Humans are sensitive to rhythms embedded in sequences of sounds, but we typically consider this skill to be part of processing for language and music, cognitive domains that we consider to be uniquely human," says Professor Heidi Harley, lead author of both studies.
"Clearly, aspects of those domains are available to other species."
Learning to sing
Harley, who is associate professor of social sciences at the New College of Florida in Sarasota, says that both studies tested dolphins at Disney's Epcot Center in Florida.
The researchers first had an adult male bottlenose dolphin position itself in front of an underwater sound projector, called a hydrophone, that produced six different 14 kiloherz, 4 second rhythms.
The dolphin was rewarded for performing a certain behaviour to each rhythm. For example, when rhythm 1 played, it waved its pectoral fin and when rhythm 2 played, it tossed a ball.
The various rhythms were played at different frequencies and tempos to ensure the dolphin was recognising rhythms instead of just frequencies or sound durations.
Another adult male was trained to produce similar rhythms using a pneumatic switch, essentially a small, air-filled ball connected to a computer that then generated sounds whenever the dolphin pressed the switch.
"The dolphin was reinforced for producing a specific rhythm to a specific object," says Harley.
"For example, when we presented him with a Batman doll, he received a fish for producing a specific rhythm, in this case, a short sound and then a long one."
"If you recall the original Batman TV series musical intro you'll probably remember the way they sang 'Bat-maaaaaaaan'," she adds.
The dolphin spontaneously vocalised to the rhythms, so the researchers started to reward the male with fish whenever it matched its 'singing' to the rhythms.
By the end of the studies, the scientists could show an object, such as the Batman doll, which represented a certain rhythm-vocalisation combo to the dolphin, and it would create the correct sounds both vocally and using the switch.
Batmaaaaaaan
Gordon Bauer, associate professor of psychology at the New College of Florida who did not work on the studies, says, "This is the first report, to my knowledge, of a nonhuman mammal's ability to discriminate rhythmic patterns."
But Bauer doubts that dolphins realise they are producing what people consider 'music'.
"I think music is a human construct," he says. "I doubt that it has pertinence to animals, although the elements of music, such as pitch, time, timbre, rhythm, etc, may be incorporated into animal communication."
Harley agrees, and hopes the everyday vocalisations of dolphins will be analysed in terms of their rhythmic content.
In the near future, she and her team are planning to test the dolphins on their ability to recognise recordings of their own rhythms by having them associate their own sound creations with identifying objects similar to the Batman doll.
