House cats have come a long way from the Near Eastern wildcat that continues to prowl the deserts in the Middle East. Evidence suggests that humans were domesticating cats in Cyprus as long as 9500 years ago, but it was likely the Ancient Egyptians who put in the work to cultivate the endearing personalities of cats we adore today. From as early as 1700 B.C.E., domesticated cats were put on ships across the Mediterranean to control pests, reaching the shores of Europe and Africa.
These lovable animals became popular companions of the Vikings, who prized cats for their rodent killing abilities. But in these colder climes, cats had another valuable purpose: their warm fur. Around 850-1050 C.E., the pelts from skinned cats were trading at high prices in Denmark, resulting in a wealth of cat skeletons unearthed from that era.
The grisly fate of these Viking cats has helped to yield a striking new discovery: modern-day, domesticated cats are larger than their ancestors. Animals typically become smaller when they are domesticated – the common pet dog, for example, is roughly 25% smaller than its wild cousin, the grey wolf. However, recently published research shows that cats have actually grown 16% larger since the Viking period.
Comparing the difference
This remarkable research started with Julie Bitz-Thorsen – then an undergraduate student at the University of Copenhagen – who was given the task of sifting through materials from archaeological sites across Denmark. Her archaeozoologist advisor, Anne Birgitte Gotfredsen, wanted to understand how the house cats of today differ from their ancient counterparts.
In the study, Bitz-Thorsen had the unenviable job of going through bags of bones stored at the Zoological Museum in Copenhagen to extract cat bones from a mix of dog, cow, horse and cat remains. The skeletons encompassed over 2,000 years, from the late Bronze Age to the 1600s. Many of the samples came from Viking pits, where the skeletons of skinned tabbies had been discarded.
Using an electronic calliper, the bones were carefully measured and compared with Danish cat bones from 1870 to the current day, resulting in this intriguing revelation that cats have become larger. The study, reported in the December 2018 edition of the Danish Journal of Archaeology, is focused on Danish cats. However, a study of cat bones from Germany in 1987 indicates that our current feline friends are indeed larger than their medieval equivalent.
Change in diet or genetics?
So how can we account for the growth in cat size? Further research is still necessary according to Claudio Ottoni, an expert on cat domestication at the University of Oslo, who says we need to understand whether the shift in size is down to a change in diet or genetics. To figure this out, Ottoni says that researchers will need to analyse the DNA in ancient samples of cat bones to identify chemical signatures of a changing diet.
But one possibility is better access to food thanks to our love affair with cats. Although our pet cats still like to attack the odd unfortunate bird or mouse, they no longer have to rely on hunting small animals for their food. Instead, they can lounge lazily on the couch, knowing we’ll be giving them a good meal and cuddle later on.