The topic of the Amazon River dolphins is a recently new one as seen by the dates of the research materials on the bibliography pages. The earliest date found was in 1989. The majority of the reference materials are dated in the 1990’s. The reference materials that I obtained are written by a small number of authors. Many authors have published two or more different reference materials on the topic of river dolphins. The majority of the authors seem to be familiar with the published works of their colleagues. Several of the authors have mentioned their fellow colleagues’ works in their own publications. The authors seem to work close with one another and learn from each other. This closeness may aid in the discovery of new information about the river dolphins in the future. The topic of the river dolphins is one enduring present investigation, and in the next few years, more information will be available.

The river dolphins have not been able to be thoroughly studied by anyone, as of yet. There is currently only one active research project concerning the river dolphins at the Institute Nacional de Pesquias da Amazonia in Manaus, Brazil. Collection of data is currently being conducted to try to fill the big gaps in the knowledge about the river dolphins. All the questions of their existence have not been able to be answered. The dolphins rarely show more than their dorsal fins which makes observational research difficult. The location of the river dolphins also makes research unfavorable. A researcher must go to the dolphins in their natural habitat. Besides the above reasons for the lack of research, I am not sure why the dolphins were not studied earlier. I think the work is timely and costly. The research has to be privately funded.

One major player is Vera Da Silva who is head of the only one active research project involving conservation and management of aquatic mammals in Manaus, Brazil. Vera Da Silva and her late husband, Robin Best, made the first rigorous studies of the behavior, ecology, and life history of the Amazon River dolphins. Morell (1997) dedicated her entire publication on Vera Da Silva and her studies of the dolphins. Best and Vera Da Silva (1989) have published several papers concerning the river dolphins. Of all the authors, Vera Da Silva seems to be the best source of information regarding all aspects of the Amazon River dolphins. She takes her works very seriously with the devotion and extent of her research. Her work was the most extensive first-hand information I obtained.

The majority of the information discovered is general but interesting. The known facts about the river dolphins concern the physical aspects, the dangers, and the myths.

With regard to the river dolphins, there is an entire conference held every two years in Chicago, Illinois. The conference is called Conference on the Biology of Marine Mammals. Some of the authors, Trujillo (1991) and Leatherwood (1991), have taken their publications to the conference to compare data with one another. This conference would be an excellent opportunity to hear the most concentrated and recent information obtained on the river dolphins.

In Morell (1997), Vera explains the physical characteristics of the river dolphins. In the Amazon River, there are two different kinds of fresh water dolphins, the boto and the tucuxi. The boto are distinctively colored, varying from a rosy blush to almost flamingo pink. Only the adults are this color. Newborns and adolescents are the common bluish-gray. Scientists do not know the reason for the pink color. The boto do not possess attractive bodies. They are shaped much like the fossil records of primitive dolphins and may even represent a relict species that adapted to freshwater millions of years ago. On the other hand, the tucuxi are a new arrival and are unquestionably related to today’s marine dolphins. The boto, like their extinct ancestors, have unfused necks and they can swim backwards. This allows the boto maneuverability in the Amazon’s flooded forests. The flooded forest is an idyll home, because they protected the dolphins from the fishermen and the abundance of fish.

Morell (1997) discusses the reproduction of the river dolphins observed by Vera Da Silva. The reproduction of the river dolphins is still hazy to researchers. One question that has not been answered concerns the interval between offspring. However, mothers and calves stay together for at least three years. This is a lengthy period of time, but apparently necessary to teach the young to fish and navigate the channels and lagoons. The theory is the river dolphins give birth at the beginning of the dry season since the water level drops making the fish easier to locate.

A major issue addressed in many of the reference materials, Morell (1997), Vidal (1993 & 1997), and Best (1989), is the concept of the Amazon River dolphins’ population. Several of the authors are working to conserve the river dolphins and concentrated their entire publications to the dangers concerning the Amazon River dolphins. The freshwater species are not yet endangered. However, the threats of pollution, overfishing, deforestation, and dams are sure to affect the numbers in the future. Problems from dams include a reduction in the food supply and separation of the dolphin populations into smaller, more isolated groups that are more susceptible to extinction. In Brazil, there are plans to meet 40% of the country’s need for electric power by the year 2000 by constructing dams in the Amazon Basin. The status of the Amazon River dolphins is currently vulnerable. The fact that the actual population size of the Amazon River dolphins is unknown makes classification extremely difficult.

Morell (1997) revealed the myths of the local people as heard by Vera Da Silva. The local people of the Amazon fear these creatures. Many myths and stories exist about the dolphins. One myth is that the dolphins can take the shape of handsome young men. They come ashore and seduce the wives and daughters. Sometimes women give birth to infants with spina bifida, a birth defect that prevents the baby’s skull from growing properly, leaving an opening in the head that resembles the blowhole of the dolphin. The locals say that the babies are the dolphins’. Other locals think that the dolphins are evil. The dolphins sometime swim under the canoes, or grab their paddles. The locals think the dolphins wanted to tip over their canoes. They are notorious for tearing a hole in the nets of fishermen and stealing all of the fish.

One reference material, Romero (1997), introduced a concept that was new to me. The concept was that the Amazon River may have flowed completely to the Pacific Ocean at one time before the formation of the Andes Mountains. The Amazon River would have been saltwater that would explain the existence of commonly found marine animals. The Andes Mountains were formed by the movement of the two continental plates crashing into one another which cut off the Amazon from the Pacific Ocean. The Amazon eventually became freshwater causing the animals to adapt to the changes in order to survive. Other commonly found marine animals in the Amazon River include shrimp and stingrays. Both of which are associated with ocean waters.

Bernardino, Fransisco Ritta (1996). Amazonian Emotions: A Moving Photographic Journey Through the Amazonian Ecosystem. Amazon Multimedia Stock.

Best, R.C., and V.M.F. da Silva (1989). "Biology, status, and conservation of Inia geoffrensis in the Amazon and Orinoco River Basins." Biology and Conservation of the River Dolphins. Occasional papers, 23-34.

Leatherwood, S., R.R. Reeves, C.L. Hill, and B. Wursig (1991). "Observations of River Dolphins in the Amazon and Maranon Rivers and Tributaries." March, June, and July in Peru. Ninth Biennial Conference on the Biology of Marine Mammals, Dec., 5-9, Chicago, Illinois.

Morell, Virginia (1997). "Looking for Big Pink: South America’s River Dolphins are Disappearing, But Vera Da Silva is Out to Change That." International Wildlife, v27, n6, 26-31.

N.L. (1997). "Amazon River Dolphin Debacle." Earth Island Journal, v12, n3, 7.

Perrin, W.F., and R.L. Brownell, Jr. (1989). "Report of the Workshop." Biology and Conservation of the River Dolphins, occasional papers, 1-22.

Romero, A., A.I. Agudo, and S.J. Blondell de Agudo (1997). "The Scientific Discovery of the Amazon River Dolphin Inia geoffrensis." Marine Mammal Science, v13, n3, 419.

Rosas, F.C.W., and Lehti, K.K. (1996). " Nutritional and Mercury Content of Milk of the Amazon River Dolphin, Inia geoffrensis." Comp. Biochem. Physiol., v115A, n2, 117-119.

Trujillo, F. (1996). "Seeing Fins." BBC Wildlife, 1416, 22-28.

I was glad to have taken your advice and started early on my literature search. I was quite happy with my topic. I did not even know dolphins were in the Amazon until a week before the topic selection occurred. I was watching the Discovery channel on a Sunday afternoon when nothing else is on. The program was about giant prehistoric whales. At the end of the program, the commentator mentioned dolphins in the Amazon River. I was quite surprised to hear that and asked my mother if she knew that dolphins lived in the Amazon. When you asked the class to pick a topic that interested us, I decided to look into the river dolphins.