‘Cetacea’ is the collective order for all whales, dolphins and porpoises. We have more than 2,500 specimens in the Museum collection, at least 500 from the UK strandings programme. Cetaceans are great indicators of wider ocean health – if there’s a problem lower in the food chain, e.g. plastic pollution, it concentrates in cetaceans. If cetacean populations are healthy, so are our oceans.
We are using 3D handheld surface scanners to map the surface of selected cetacean skulls to produce a digital surrogate of each specimen. 3D modelling can help researchers gain an understanding of large animals like whales, which are difficult to observe in the wild or to handle as specimens.
Cetaceans are widely distributed and diverse in species richness, morphology and ecology, exhibiting great variety in body size, behaviours and adaptations. For example, odontocetes (toothed whales) have evolved the ability to echolocate; and mysticetes (baleen whales) have evolved their baleen filter-feeding systems as well as the largest body sizes of any animals ever to live on Earth. These adaptations make cetaceans a fascinating and valuable group for studying morphological diversity.
The Digital Collections Programme is working to increase access to the collections for researchers and others. For many specimens such as pinned insects, digitisation is achievable as a ‘mass production’ workflow, however the programme also needs to explore more challenging specimens such as very large whale skulls, to examine what can be achieved with technologies including 3D surface scanning. Once complete, 3D models will be released on the Museum’s Data Portal and Sketchfab account.
To image these large specimens we use mobile, handheld structured light scanners to capture the profile of the surface, including any cracks, peaks, troughs and texture. These scanners were originally designed for industry, where they are often used in quality control. The scanner sometimes needs some help tracking the its movement around these organic specimens which can be topologically complex and have smooth, featureless surfaces. We can use target dots on the surface of the specimen. These are archival self-adhesive paper that sticks well, but does not harm the specimen. Our scanner uses the dots’ positions along with natural features on an object to track its location and orientation.
3D surface scanning lends itself well to large, static structures like skeletons. We can get much more information on complex anatomical structures like the skull using 3D approaches than by 2D imaging. The output of these scans is dense polygon mesh models, which we can analyse to reconstruct in great detail how and why the skull evolved the way it did.
How will this data be used?
Museum researchers Dr Natalie Cooper, Prof Anjali Goswami and Dr Ellen Coombs will use the finished 3D datasets to perform comparative analysis between the cetacean skulls to gain further understanding into how these animals developed and adapted to life in the ocean. Datasets from this project will also be shared on http://phenome10k.org, a free online repository for 3D scans of biological and palaeontological specimens created by Prof Goswami in 2015, to enable comparison with other Vertebrates.
While previous studies of whale skulls have relied on really simple length measurements, we can use really detailed 3D methods to accurately reconstruct how these complex shapes evolved and even estimate what their ancestors might have looked like. We can look at how changes in reproduction or diet influenced the shape of whale skulls, and we can even analyse how they have evolved in response to previous changes in climate and ocean circulation, giving us much better understanding of the challenges they will face in the future.
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