07/01/2014 11:27 GMT | Updated 23/01/2014 10:53 GMT

Conjoined 'Siamese' Gray Whale Twins Could Be First Ever (VIDEO, PICTURES)

Images and footage of what could be the first documented discovery of conjoined gray whale calves have emerged.

The shots were posted to the Guerrero Negro Verde Facebook page on Sunday with the information that the carcasses had been found in Mexico's Laguna Ojo de Liebre, or Scammon’s Lagoon.

A translated statement reads: “Unfortunately, the specimen died. [Its] survival was very difficult.”

Outdoors blogger Pete Thomas points out a database search at the Natural History Museum of Los Angeles County does not reveal any previously published instances of conjoined gray whale twins – though they have reportedly occurred in species of fin, sei and minke whales.

He also cites Alisa Schulman-Janiger, an American Cetacean Society researcher as stating the twins were underdeveloped and had probably been prematurely born.

Footage of the discovery was posted to YouTube where some commenters speculated as to whether the birth defect was perhaps related to Japan's Fukushima nuclear plant disaster.

The carcasses, which have reportedly been collected for study, are said to have measured 2.1m in length compared to the normal length of newborn gray whales which is between 3.6m and 4.8m.

Adult gray whales reach up to 14m in length and have recently returned from the brink of extinction, the Marine Mammal Centre writes. Current worldwide population levels are estimated to be around 26,000.