A newly identified prehistoric whale had unusual adaptations that may have allowed it to hunt along the seafloor millions of years ago.
An ancient whale that lived millions of years ago had a skull so dramatically distorted that its face appeared pushed to one side. Its bony nostrils were displaced entirely to the left, and its oversized snout curved sharply downward. Scientists have identified the animal as Scaphokogia huachafo, an extinct pygmy sperm whale with the most extreme facial asymmetry ever documented in a cetacean.
The fossil dates to the Late Miocene, approximately 6.3 to 5.6 million years ago, and belonged to a whale measuring about 2.7 meters (8.9 feet) long. Researchers believe its skull may also represent the greatest facial asymmetry known in any mammal.
Why This Ancient Whale Had Such an Unusual Skull
Most vertebrates have skulls that are approximately symmetrical, with corresponding structures on either side of the head. Toothed whales are an exception. Their skulls have evolved asymmetrical shapes to accommodate specialized organs involved in producing sound and echolocation, allowing them to navigate and detect prey underwater.
“Cranial asymmetry in toothed whales is directly linked to the development of fatty structures in the forehead that are involved in sound production. But in Scaphokogia huachafo, this asymmetry went far beyond the area around the blowhole. Both bony nostrils are shifted entirely to the left side of the skull, while the facial bones differ dramatically in size and position. The skull looks completely crooked,” explains Aldo Benites-Palomino, lead author of the study. He investigated the fossil during his doctoral research at the University of Zurich and is now an assistant professor at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU).
Built to Hunt Along the Seafloor
The whale’s unusual anatomy suggests a feeding strategy very different from that of modern sperm whales, which pursue squid in deep ocean waters. Scaphokogia huachafo appears to have been adapted for searching for food along the bottom of shallow coastal seas. Its thick, tubular snout contained dense bone and hardened cartilage that added weight toward the front of its body. The snout angled downward by 31 degrees, while reconstructions of the joint between the skull and first neck vertebra suggest the animal could lower its head by as much as 55 degrees.
“The entire cranio-cervical complex is modified to point the snout directly toward the bottom,” explains Gabriel Aguirre-Fernández, study co-author and doctoral advisor at the University of Zurich. “The combination of dense bone, the downward-curving snout and the flexible neck articulation allowed the animal to move directly above the seabed and feed close to the sediment.”
Unlike some modern marine mammals that forage along the bottom, Scaphokogia lacked specialized facial whiskers and visual adaptations associated with locating prey in sediment. Researchers therefore suspect it relied on its unusually developed biosonar system to detect food hidden in soft seabed deposits. This remains a hypothesis based on its anatomy rather than direct evidence of its hunting behavior. Its specialized ecological niche apparently disappeared as ocean conditions changed near the end of the Miocene.
A Fossil Skull That Looked Almost Too Strange to Be Real
The skull was recovered in the mid-1990s from the Pisco Formation in southern Peru, a desert region famous for exceptionally preserved marine fossils. Benites-Palomino encountered the specimen in 2015 while working on his bachelor’s thesis at the Museo de Historia Natural in Lima. Its extreme shape initially raised the possibility that geological forces had distorted the skull after the animal died.
“The initial suspicion with skulls this distorted is always taphonomy – that the specimen may have been flattened or twisted by sediment pressure over millions of years,” says Benites-Palomino. “But the sutures are fully closed, and there are no fractures, pathologies or deformations elsewhere on the skull. This was genuine biology, not a result of poor preservation.”
A Peruvian Name for an Extraordinary Whale
The researchers chose a species name that reflects the animal’s unconventional appearance. Huachafo comes from Peruvian Spanish and describes something extravagant, flashy, bizarre, or aesthetically excessive.
“In Peru, huachafo is an everyday word for anything that is flashy, over-the-top, bizarre, extravagant, or difficult to categorize aesthetically,” says Benites-Palomino.
“When we looked at the proportions of this whale – with its face strongly shifted to the left and its oversized, downward-curving snout – it broke every rule of symmetry and elegance seen in living cetaceans. Its anatomy is so extravagant and odd that huachafo seemed the perfect name for it.”
Reference: “Extreme cranial asymmetry in extinct benthic feeding sperm whales” by Aldo Benites-Palomino, Marcelo R. Sánchez-Villagra, Florencia Paolucci, Jorge Vélez-Juarbe, Alberto Collareta, Apolline Alfsen, Alton Dooley, Dan Omura, Mario Urbina, Rodolfo Salas-Gismondi and Gabriel Aguirre-Fernández, 9 November 2026, Communications Biology.
DOI: 10.1038/s42003-026-11074-2
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