Dinosaur demise in light of their alleged perennial polar residency
- 261 Downloads
The end-Cretaceous biological crisis is represented by the demise of the non-avian dinosaurs. However, most crucial biologically was the elimination of the photosynthesizing marine phyto- and zooplankton forming the base of the marine food chain. Their abrupt demise attests to sunlight screening darkening the atmosphere for a few years. Alvarez et al. (Science 208:1095–1108, 1980. doi: 10.1126/science.208.44) noticed in deep marine end-Cretaceous sediments an anomalous rise in the chemical element iridium (Ir), which is rare on planet Earth and thus suggests an extraterrestrial origin through an impact of a large asteroid. This impact would have ejected enormous quantities of particles and aerosols, shading the solar illumination as attested to by the elimination of the marine photosynthesizing plankton. Such a dark period must have affected life on land. The apparent cold-blooded non-avian dinosaurs, which were used to living in open terrains to absorb the solar illumination, became inactive during the dark period and were incapable of withstanding predators. This was in contrast to cold-blooded crocodilians, turtles and lizards that could hide in refuge sites on land and in the water. Dinosaur relics discovered in Cretaceous Polar Regions were attributed to perennial residents, surviving the nearly half-year-long dark winter despite their ability to leave. The polar concentrations of disarticulated dinosaur bones were suggested as having resulted from a catastrophic burial of a population by floods. However, this should have fossilized complete skeletons. Alternatively, herds of dinosaurs living in high latitudes might have been sexually driven to spend the half year of continuously illuminated polar summer for mating rather than for nourishment, in which the lower latitudes provided as well. The aggressive mating competitions would have left victims among the rivals and of young ones incidentally trampled over, all being consumed and their skeletons disarticulated. Accordingly, the alleged ‘polar dinosaurs’ do not challenge the logical conclusion that the non-avian dinosaurs were cold-blooded, as a result of which they became inactive and subjected to predation during the end-Cretaceous dark period.
KeywordsPolar dinosaurs End-Cretaceous biological crisis Cold-blooded dinosaurs Annual migration for mating
I thank Bevie Katz and Prof. Dr. Eberhard Frey (Dino; State Museum of Natural History Karlsruhe, Germany) and the anonymous referee for their constructive comments. My grandson Eyal interest in dinosaurs and the cause of their extinction instigated the research.
- Abramovich S, Keller G (2003) Planktonic foraminiferal response to the latest Maastrichtian abrupt warm event: a case study from South Atlantic DSDP site 535A. Mar Micropaleontol 919:1–25Google Scholar
- Fiorillo AR, McCarthy PJ, Flaig PP (2010) Taphonomic and sedimentologic interpretations of the dinosaur-bearing Upper Cretaceous Strata of the Prince Creek Formation, Northern Alaska: insights from an ancient high-latitude terrestrial ecosystem. Palaeogeogr Palaeoclimatol Palaeoecol 295:376–388CrossRefGoogle Scholar
- Hotton III N (1980) An alternative to dinosaur endothermy: the happy wanders. In: Thomas RDK, Olson EC (eds) A cold look at warm-blooded dinosaurs. AAAS Selected symposium. Westview Press, Boulder, Co, pp 311–350Google Scholar
- Hurum JH, Milàn J, Hammer Ǿ, Midtkandal I, Amundsen H, Sæther B (2006) Tracking polar dinosaurs—new finds from the Lower Cretaceous of Svalbard. Norw J Geol 86:397–402Google Scholar
- Keller G (2014) Deccan volcanism, the Chicxulub impact, and the end-Cretaceous mass extinction: coincidence? Cause and effect? In: Keller G, Kerr AC (eds) Volcanism, impacts, and mass extinctions: causes and effects, vol 505. The Geological Society of America Special Paper, pp 57–89. doi: 10.1130/2014.2505(03)
- Keller G, Bhowmick PK, Upadhyay H, Dave A, Reddy AN, Jaiprakash BC, Adatte T (2011) Deccan volcanism linked to the Cretaceous–Tertiary boundary mass extinction: new evidence from ONGC wells in the Krishna-Godavari Basin. J Geol Soc India 78:399–428. doi: 10.1007/s12594-011-0107-3 CrossRefGoogle Scholar
- Lewy Z, Dvorachek M, Perelis-Grossowicz L, Ilani S (2011) Lower Eocene crustacean burrows (Israel) reflect a change from K- to r-type mode of breeding across the K–T boundary clarifying the process of the end-Cretaceous biological crisis. In: Chen D (ed) Advances in data, methods, models and their applications in geoscience. InTech, pp 313–336. ISBN:978- 953-307-737-6Google Scholar
- Machalski M (2005) Late Maastrichtian and earliest Danian scaphitid ammonites from central Europe. Taxonomy, evolution and extinction. Acta Palaeontol Pol 50:653–696Google Scholar