It has taken two years of study, but scientists a Michigan State University have confirmed the existence of a two-headed bull shark.
The shark, found in the uterus of an adult shark caught near Florida, in the Gulf of Mexico in April of 2011, was initially thought to be conjoined twins. While other species of sharks have been discovered with two heads, this is the first bull shark. Michigan State University led the study that confirmed the discovery, which appeared in the Journal of Fish Biology.
The condition is called axial bifurcation. The embryo begins division into twins, but the process is incomplete and results in mutation. There is no known reason that the process of division is interrupted. The difference is that in conjoined, or “Siamese” , twins occur due to incomplete division of the ovum in utero, resulting in connections of various size, area, and severity. Axial bifurcation, or polycephaly, is a complete duplication in development of the head. The MSU staff, with careful examination, determined that this particular shark is not a conjoined twin, but a shark with two complete heads.
There cannot be any specific conclusions drawn from the discovery, as only one has been found. It would take more than one to establish the cause and significance of the discovery. Abnormalities such as this two-Headed bull shark, are difficult to find because the sharks generally die shortly after they are born. This particular bull shark discovery was found in the uterus of an adult bull shark. The 2-headed shark died shortly after the fisherman discovered it. According to Michael Wagner, MSU assistant professor of fisheries and wildlife, the two-headed fetus had little or no chance of surviving in the wild.
Using an MRI, the team at Michigan State University were able to establish the existence to two completely distinct heads, hearts, and stomachs, with a joined lower body with only one tail.
The fact that two-headed sharks, especially this bull shark, rarely survive in the wild may be bad news for scientists who wish to study them, but good news for swimmers in tropical areas. Bull sharks are aggressive and are among the most likely to attack humans because they prefer shallow tropical coastlines… where people prefer swimming. The bull shark generally head butts their prey before they attack and this shark would have two heads for attacking! Bull sharks are joined by great white sharks and tiger sharks as the most likely to attack humans.
Discoveries of two-headed organisms such as lizards and snakes are not uncommon. These are generally born in captivity and are discovered by caretakers, thus documented more frequently than other species.
Some people are surmising that pollution is the reason behind the abnormally formed shark. While pollution could be a contributor, there is no scientific support to prove this theory. In fact, scientists do not know what factors are involved in this mutation. They continue to study the samples at hand, and perhaps one day will have more answers.
