Macroraptorial sperm whale

They were all likely the apex predator of their habitats, comparable to the modern day killer whale (Orcinus orca), and achieved great lengths, with one species—Livyatan—measuring about 13.5–17.5 m (44–57 ft).

This encompassed the entire breadth of the snout in Livyatan and Brygmophyseter;[3][7] Zygophyseter and Acrophyseter, instead, had reduced basins indicating beaks.

[2][4] The elongated lumbar vertebrae of Zygophyseter indicate it had larger multifidus and longissimus back muscles and was, thus, faster than the modern sperm whale which,[2] comparable to other large open-ocean animals, travels horizontally at 4 km/h (2.5 mph).

[8] Using their large and deeply rooted teeth, wide-opening jaws, and great size, they likely fed on a variety of sea life, including fish, cephalopods, seals, and small whales and dolphins, occupying a niche similar to the modern day killer whale (Orcinus orca).

[7][10][11][12] In sperm whales, the supracranial basin holds the spermaceti organ, a series of oil and wax reservoirs which aids in echolocation.

The large temporal fossa depressions on the skull of raptorials is probably descended from a common ancestor (plesiomorphy).

The presence of enamel is thought to be an ancient and basal characteristic, as it is present on the teeth of fetal modern sperm whales.