How I came to paint a reddish-brown giant penguin
Shame on me, the first story in this blog does not deal with sabretooths, but I warned you I could post about many different things… Instead of a sabretoothed cat, a sword-beaked giant penguin. I just came across this post in the NGS web
I did that penguin illustration a few months ago for the April 2011 issue of NGM, but had forgotten about it until I saw it last week on the june issue of the Spanish edition of the magazine. It is not everyday that you have the opportunity to reconstruct an extinct vertebrate for which you have direct information about its coat colour, and that is precisely the case with Inkayacu. The fossil specimen, from the Oligocene of Peru, miraculously preserves evidence of the bird’s feathers, with tiny pigment packages known as melanosomes. These structures show that the bird did not have the solid black back of most extant penguins, and unlike any of them its plumage had reddish-brown tints. However, the fossils don’t show us the exact coat colour pattern of Inkayacu, they just show the presence of the brown pigments. So the pattern you see in the illustration was based on that seen in various modern penguins and other aquatic birds. I avoided the dark brown chest shown in several previous reconstructions, because I wanted to give the animal somewhat lighter underparts which are so common in vertebrates that spend a lot of their time swimming -one more manifestation of the old theory of “counter-shading” in animals, also known as “Thayer’s Law”. Recent studies suggest that the advantages of this pattern are not so obvious for land animals, but they remain convincingly clear for animals that spend time in the water because they benefit from a “background match” mechanism, and I would guess that the extreme pattern (dark above, light below) of modern penguins has so much to do with their marine habits as it has with anything else.
Hopefully one day somebody may find a wonderfully preserved sabretooth fossil which may tell us something about those animal’s coats, but meanwhile we are left to speculate about their patterns. What a pity.