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Updated: Jul 5, 2026
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Published on: January 16, 2026
Higher origination and extinction rates in larger mammals
Lee Hsiang Liow1, Mikael Fortelius, Ella Bingham
1Center for Ecological & Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo, Norway.
Summary
Large mammals exhibit faster evolution with higher origination and extinction rates, leading to shorter durations. Small mammals, however, show greater survivorship due to adaptive behaviors like "sleep-or-hide" (SLOH).
Area of Science:
- Paleontology
- Evolutionary Biology
- Mammalian Evolution
Background:
- Understanding macroevolutionary rates and life-history traits is crucial for evolutionary patterns.
- Previous research on mammal evolution rates has yielded inconsistent results.
- The relationship between body size and evolutionary rates in mammals remains debated.
Purpose of the Study:
- To investigate whether large or small mammals evolve at faster rates.
- To analyze evolutionary patterns using a comprehensive fossil dataset.
- To explore the role of behavioral adaptations in mammalian evolutionary dynamics.
Main Methods:
- Utilized a large fossil dataset of Neogene Old World (NOW) mammals.
- Controlled for sampling biases and calculated per capita origination/extinction rates.
- Employed capture-mark-recapture (CMR) methods to estimate survival probabilities.
Main Results:
- Large mammal genera and species demonstrate higher origination and extinction rates, resulting in shorter durations.
- This contrasts with molecular studies suggesting faster evolution in smaller animals.
- Small mammals with 'sleep-or-hide' (SLOH) behaviors exhibit higher survivorship and lower origination rates.
Conclusions:
- Body size influences mammalian evolutionary rates, with larger mammals evolving faster but having shorter durations.
- Behavioral adaptations, such as SLOH, provide environmental buffering and enhance survivorship in small mammals.
- Environmental interactions with phenotypic variation, not just molecular rates, shape macroevolutionary patterns.
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