Today’s heaviest flying bird, the 48-pound Kori Bustard, was a lightweight compared to dinosaur-era flying reptiles known as pterosaurs, according to a new study that presents a novel method for estimating pterosaur weight.
Calculations based on footprints left behind by pterosaurs, also known as pterodactyls, reveal these animals weighed up to 320 pounds. The study, published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology on 1 January 2011, is believed to be the first to use fossilized footprints to infer the body weight of an extinct animal.
Just how such large reptiles were able to fly has been a conundrum until the last few decades. Research published 24 November 2010 in the Proceedings of the Royal Society B has moved a step closer to understanding just that. Study author Colin Palmer, an engineering and paleontology expert from the University of Bristol, made models of pterosaur wings using resin, carbon fiber and latex rubber and tested them in a wind tunnel. He was inspired to do the tests after discovering that previous research on pterosaur flight was only based on pre-1950s data on aircraft wing behavior. He says that research had overestimated the efficiency — that is, the ratio of lift to drag — of pterosaurs in flight. Palmer’s research, by comparison, also factored in the wing bones, which produce additional drag.
Palmer found that while pterosaurs are less efficient flyers than many birds today, they made up for this by being able to fly and land very slowly. This is quite a different flying style to the albatrosses they are often compared with.
If we want to imagine how the pterosaur flew, we can look to the modern day frigatebird, says Palmer. This large black seabird lives on tropical Pacific and Atlantic islands and is best known for its vivid red chest, which it puffs out to attract a mate. Palmer says frigatebirds also fly relatively slowly and make use of updrafts and thermal lifts over land and sea.
- Tai Kubo, “Estimating body weight from footprints: Application to pterosaurs”, Palaeogeography, Palaeoclimatology, Palaeoecology 299 (1-2): 197-199 (1 January 2011).
- Colin Palmer, “Flight in slow motion: aerodynamics of the pterosaur wing”, Proc. R. Soc. B published online before print 24 November 2010, doi:10.1098/rspb.2010.2179