The Siamese whales where dead when they were discovered in the Ojo de Liebre lagoon in Baja California, a popular site for hundreds of whales who migrate annually to the warmer waters.
Scientists and officials from the National Natural Protected Areas Comission (CONNAP) verified the finding after inspecting the whales that had since washed ashore.
Weighing nearly half a tonne, the whales were found linked at the waist with two full sets of tail fins and heads. However scientists believe the calves may have been stillborn or not yet at full gestation at the time of birth.
Usually a full-term gray whale calf would measure about four metres in length. The conjoined calves were much shorter, measuring roughly two to three metres, and as such they were probably between eight and 10 months along. A normal gray whale gestation lasts 13.5 months, confirmed mammal experts at the Natural History Museum of Los Angeles.
However experts also cautioned that the projected ages of the deceased whale calves are based on what is known about the size and length of single foetuses and their respective gestation period.
“In the case of twins, the mother has to provide nourishment for two growing foetuses and that may result in two slightly smaller foetuses rather than one normal-sized one,” Jim Dines from the National History Museum in LAexplained.
“These were pretty sizeable.There’s a fair chance the mother was trying to deliver them and couldn’t.” he added
The calves mother has not been spotted in the surrounding area where they were found and as such it is unclear whether she survived the birth or not.
According to Michael Moore, a veterinarian at the Woods Hole Oceanographic Institution in Massachusetts it’s not unheard of in large whales to have Siamese twins, but because of their reproductive biology and the difficulties of raising a calf in an aquatic environment, dolphins and whales are more likely to have a single baby, he explained.
Even if conjoined whale calves managed to make it to full term, Moore stressed it was doubtful they would ever survive, especially since they would have to coordinate coming up to surface for air.