When the wild things are: Defining mammalian diel activity and plasticity

Area of Science:

• Ecology
• Animal Behavior
• Chronobiology

Background:

• Circadian rhythms are crucial for species adaptation and understanding behavior.
• Existing frameworks for assessing species' temporal activity are insufficient, especially during rapid ecological change.
• A standardized method is needed to accurately compare diel activity across species.

Purpose of the Study:

• To create a standardized framework for assessing diel activity in mammals.
• To analyze the accuracy of existing diel classifications and identify patterns of plasticity.
• To investigate the relationship between species traits and their diel activity patterns.

Main Methods:

• Utilized a global network of 8.9 million mammalian observations from 38 countries.
• Developed a library of 14,587 standardized diel activity estimates for 445 species.
• Compared new estimates with reference literature and analyzed plasticity in relation to anthropogenic change.

Main Results:

• Less than half of species' diel activity estimates agreed with existing literature.
• Many species exhibited multiple diel activity patterns, indicating high plasticity.
• Body size and distributional extent significantly correlated with diurnal or nocturnal activity.

Conclusions:

• Current diel activity classifications are often inaccurate and lack consistency.
• Species diel activity is dynamic and influenced by anthropogenic pressures.
• A novel, quantitative framework is essential for consistent and accurate assessment of species' diel activity and plasticity.