Scientists on Sunday found conjoined gray whale twins in Mexico's Laguna Ojo de Liebre, in Baja, Calif. It's thought to be the first documented case of its kind.

The calves, which were dead upon discovery, are believed to have been miscarried as a result of their condition. According to American Cetacean Society researcher, Alisa Schulman-Janiger, it's possible the mother died as well due to the whales' underdevelopment. Scientists obtained the carcass for further study.

Gray whales are one of the ocean's greatest travelers, swimming around 12,000 miles roundtrip from Alaskan waters in the summer to the Baja area in the winter. These whales are protected by international law because they were on the brink of extinction in the 20th century. There are about 21,000 Pacific gray whales in the world, according to National Oceanic and Atmospheric Administration.

Environmental group Guerro Negro Verde uploaded photos of the Siamese twin gray whales to its Facebook page on Tuesday.

Image: Farah Castillo