Conjoined Whales Wash Up In Mexico: 'Exceptionally Rare' Gray Whale Calves May Have Been Miscarried
An "exceptionally rare" pair of conjoined whales that washed up in a Mexican lagoon on Sunday may be the first documented case among gray whales. The dead conjoined whales were found by fishermen in Laguna Ojo de Liebre, on the coast of Baja California, a breeding site for gray whales.
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The conjoined whales had two fully-formed heads and tail fins, according to Benito Bermudez, a marine biologist with Mexico's National Natural Protected Areas Commission. Bermudez also said that such conjoined whales were "without any precedent" in the area.
At seven to 10-feet long, the conjoined gray whales were smaller than normal and may have been miscarried. The gray whale gestation period is 13.5 months; given the sizes of the conjoined whales, they may have been between 8.5 and 10.5 months old when they were born, according to Jim Dines of California's Natural History Museum of Los Angeles County. Dines made that estimate based on the sizes of single gray whale fetuses, so he says it's only an educated guess.
"In the case of twins, the mother has to provide nourishment for two growing fetuses and that may result in two slightly smaller fetuses rather than one normal-sized one," Dines said. "These were pretty sizable. There's a fair chance the mother was trying to deliver them and couldn't."
Hundreds of gray whales migrate down from the Arctic to the lagoons of Baja California in winter for mating and birthing. During the gestation period, the pregnant whales return to the Arctic, where they feed during summer; the pregnant whales return to the Mexican lagoons to give birth. Females that have just become pregnant assist the whales that are giving birth, acting as midwives.
The conjoined gray whale remains were collected for further study. Although this is the first instance of conjoined gray whales, other whales species such as minke whales have been documented before.
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