fossils

The fossil whale with a full belly

569841f91c850ea93628ec1ef8661217

Katherine
Kurowski

Guest Writer
Today’s beaked whales (Ziphiidae) dive hundreds of meters to chase after their prey: seafloor-living squids, fishes, and crustaceans. However, one remarkable fossil suggests an ancestral species of these whales found its food near the water’s surface.

In 2014, along the southwestern coast of Peru, palaeontologists Olivier Lambert and colleagues unearthed the skeletons of an ancient beaked whale, or ziphiid, and numerous sardine-like fishes preserved inside the whale’s chest and head area. The rocks entombing the fossilized remains of the whale, a specimen of Messapicetus gregarius, and fish, Sardinops sagax, accumulated as seafloor sediment in the Late Miocene age, nine to ten million years ago.


Lambert and colleagues described the fish’s scales as showing little to no signs of stomach acid exposure, suggesting the whale had gorged on these fish hours before dying and sinking to the seafloor. The fish skeletons in the head area may have been the ziphiid’s vomit.


The paleontologists calculated the ancient whale’s last meal to have been composed of 40 to 60 fish, each averaging 39 cm (15 in) in length and weighing 410 g (14 oz), with a total weight of 16 and 25 kg (35-55 lbs) – similar to its modern-day relative’s fare.


These fish, if anything like their similar-sized modern-day kin, fed at or near the water’s surface and would not have scavenged on the dead whale’s carcass, leading researchers to propose that this fossil discovery supports the hypothesis that early ziphiid species swam near coastal surface waters. Only after the appearance of dolphins – their competitors ­– did beaked whales evolve to become the deep divers of today, having been driven out by the limited supply of surface-living food.


Read the original research in The Royal Society Publishing.

Image Credit: Alberto Gennari

569841f91c850ea93628ec1ef8661217

Katherine
Kurowski

Guest Writer


http://sulc.us/3687j
http://www.eartharchives.org/articles/the-fossil-whale-with-a-full-belly/