Sperm whales (Physeteroidea) are a fascinating group of odontocetes (toothed whales), displaying a high size disparity. Extant sperm whales share a series of unusual ecological, behavioural and morphological features that clearly differentiate them from most other odontocetes. They principally feed on cephalopods, which they hunt at important depths on the continental slope and in submarine canyons. Diving records up to 3000 meters depth and 138 minutes duration have been reported for Physeter. Predation techniques are poorly known at such depths, where darkness is complete. However, it is clear that the sonar (echolocation system) of these animals plays an important role in prey detection. Preys are caught and swallowed integrally by suction, freeing the teeth from any prehension function.
This project tries to seek answers to the following questions :
- What do the morphologies observed tell us about the ecology of extinct sperm whales? What can we infer from their anatomy about their feeding strategies, prey types, and habitats?
- Can we find marks of the predator-prey interactions of these fossil sperm whales with other marine animals on the fossilized teeth of the predators and the skeletons of potential preys?
- Is there a relationship between the diversification of a predator type and the evolution of potential preys?
- What can be said about the extinction of most of the sperm whale lineages if we confront these extinction events to the climatic changes (for example the drastic cooling period following the mid-Miocene climatic optimum) and the evolution of the biodiversity of other animals during the Neogene (for example the Pliocene diversification of true dolphins)?
- Is the evolutionary history of deep diving teuthophagous sperm whales synchronous with the diversification of ecologically similar beaked whales (Ziphiidae) and with climatic events?
The objective of this project is to investigate the high diversity of morphologies and sizes among fossil and modern sperm whale lineages in order to reconstruct the evolution of their predation modes (raptorial against suction feeding), prey types (squid, fish, and/or other marine mammals), and habitats (deep sea, shallow water), and to define the potential triggers (e.g. climatic changes) of the main ecological shifts. To reach this goal, previously collected and newly excavated Oligocene, Miocene, and Pliocene fossil remains will be used, both of sperm whales and potential preys.
Taking account of up-to-date comparison material and the most recent studies of modern toothed whale ecology and functional anatomy, the application of various investigation techniques in the research fields considered (including modern techniques of data acquisition, e.g. CT scan, scanning electron microscopy) will provide answers to questions directly related to the complex evolutionary history of sperm whales: chronology of diversification and extinction phases, evolution rate, determining factors (prey types, competition, climatic changes…), adaptations and habitat shift, evolutionary convergences…
Related publications
- Bardet, N. et al. A giant chelonioid turtle from the Late Cretaceous of Morocco with a suction feeding apparatus unique among tetrapods. PLoS ONE 8, 1-10 (2013).
- Bianucci, G. et al. A Miocene relative of the Ganges River dolphin (Odontoceti, Platanistidae) from the Amazonian Basin. Journal of Vertebrate Paleontology 33, 741-745 (2013).
- Lambert, O., de Muizon, C. & Bianucci, G. The most basal beaked whale Ninoziphius platyrostris Muizon, 1983: clues on the evolutionary history of the family Ziphiidae (Cetacea: Odontoceti). Zoological Journal of the Linnean Society 167, 569-598 (2013).
- Lambert, O. & de Muizon, C. A new long-snouted species of the Miocene pontoporiid dolphin Brachydelphis and a review of the Mio-Pliocene marine mammal levels in the Sacaco Basin, Peru. Journal of Vertebrate Paleontology 33, 709-721 (2013).
- Beatty, B. L., Vitkovski, T., Lambert, O. & Macrini, T. E. Osteological associations with unique tooth developement in manatees (Trichechidae, Sirenia): a detailed look at modern Trichechus and a review of the fossil record. The Anatomical Record 295, 1504-1512 (2012).
- Geisler, J. H., Godfrey, S. J. & Lambert, O. A new genus and species of Late Miocene inioid (Cetacea: Odontoceti) from the Meherrin River, North Carolina, U.S.A. Journal of Vertebrate Paleontology 32, 198-211 (2012).
- Lambert, O. et al. Walvissen uit het Waasland. HONA 47, 37-40 (2012).
