Researchers report that long-term climate shifts helped drive the diversification of body shapes across the order Carnivora. They conclude that modern carnivorans — from bears and wolves to seals and cats — can trace their diversity to mongoose-like ancestors with long bodies and small, round ears.
The study, led by Chris Law of the University of Washington and published in Proceedings of the Royal Society B, measured skeletal shape on more than 850 specimens held at 17 natural history museums. The sample included almost 200 species in total: 118 extant species and 81 extinct ones. The team used these measurements to test how body form changed over deep time.
The authors identify two climate transitions with distinct effects. The Eocene–Oligocene transition, about 34 million years ago, coincided with major shifts between carnivoran families — for example between the lineages that led to cats and to dogs. Later, the Mid‑Miocene Climate Transition, about 15–13 million years ago, corresponded with changes within families, such as variation among canid species. The study thus provides a clearer timeline for body-shape evolution, but it remains unclear how directly these deep-time patterns relate to modern environmental change; further work is needed.
- Ancestors: mongoose-like body plan
- Data: >850 specimens, ~200 species
- Two key shifts: ~34 Ma and ~15–13 Ma
Difficult words
- diversification — increase in number and variety of types
- carnivoran — a mammal in the order Carnivoracarnivorans
- extant — still living today, not extinct
- extinct — no longer living anywhere today
- transition — period of change from one state
- lineage — a sequence of species descended from ancestorslineages
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Discussion questions
- How might the deep-time patterns described in the article relate to modern environmental change? Give reasons for your view.
- What is the value of including extinct species, as well as extant ones, when studying evolution and biodiversity?
- How could a clearer timeline for body-shape evolution affect conservation decisions or scientific research priorities?
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