Having a ‘whale’ of a time with Jane the dinosaur at Leicester

Posted by lcb14 at Oct 28, 2018 10:10 PM |
Dr Robert Goodall tell us more about his palaeontology research at Leicester...

I am a palaeontologist, working at the University of Leicester, and for those who don’t know, a palaeontologist studies the evolution of life on this planet, using fossils (and other information, such as the composition of rocks), to work out what life and environments looked like millions of years ago. The most well-known aspect of palaeontology is the study of dinosaurs, from their appearance on earth over 230 million years ago, to their extinction 65 million years ago. The University of Leicester’s resident T-Rex Jane (who turns 10 this week) is one such dinosaur, and she roamed an area that would later become the state of Montana in the USA about 66 million years ago.

When I was much younger, it was dinosaurs that got me excited about palaeontology, and I have been obsessed with them ever since I was 5 years old. However, my current research deals with a very different, but no less exciting, group of animals. I study the evolution of whales and dolphins. These amazing creatures are found all over the modern world, in every ocean, and are a vital part of the marine food web. They range in size and shape from the smallest dolphins, which are about the same size as your front door, to the largest animals that have ever lived on earth, the blue whale, whose heart alone weighs the same as two large humans. Whales and dolphins fall into two main groups, those with teeth (such as killer whales), that hunt and feed on fish, squid and other animals, and those that feed using baleen plates to sieve plankton or small fish after taking huge gulps of water. My most recent research has focussed on what the earliest whales ate, before they separated into these two groups.

Rob's research focuses on whale evolution
Rob's research investigates whale evolution

All whales share an ancestor with hoofed mammals, such as deer, cows, and camels, and the closest modern relative to whales is the hippopotamus. The split between hoofed mammals and the earliest whales happened about 55 million years ago, not long after the extinction of the dinosaurs. Because of this link to hoofed mammals, the earliest whales were very strange. They were furry, pig sized animals, living in and near rivers in what is now Pakistan, using the water to avoid predators, and feed. One example is Pakicetus, which had ear bones very similar to modern whales. By 45 million years ago, whale ancestors became more adapted to water, spending more of their time living, and feeding in rivers, estuaries and the open ocean. They developed webbed feet, and larger bodies, with stronger tails to help with swimming. However they still had to come out on to the land to breed, much like modern seals and sealions. Over the next 5-10 million years whales got much bigger and evolved to spend all of their time underwater. Their back limbs became small stumps, and their tails grew longer and developed the tail shapes we see in modern whales. It is after this point that whales started to split into toothed and baleen whales, about 25 million years ago.

Working at Leicester, I have discovered how the diets of the earliest whales changed as they became adapted to water. Previously it was thought that as whales spent more time in the water their diets simply changed from fish to larger animals, including other whales. However we now know that their diets were more varied, with some feeding on fish, others on large marine animals (including other early whales), and a few feeding on small crustaceans, like krill. This helps us build up a picture of what these animals ate, but there is still much more we can learn about these amazing creatures. Working alongside other palaeontologists at Leicester and around the world, I am now pioneering new ways to study how diet changed during the split between toothed and baleen whales.

Dr Robert Goodall, Honorary Fellow

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