Sexual selection, temperature, and the lion's mane

Combining field observations with experiments using life-sized dummy lions, researchers tested what information a male's mane signals. Darker manes indicated higher testosterone and better nutrition, and resident males responded with more caution to dark-maned dummies while females preferred them. Mane length signalled recent fighting history. The mane therefore functions as an honest advertisement of male quality, though it carries a thermoregulatory cost in hot climates. The study elegantly linked an iconic ornament to condition-dependent signalling and partner choice, and it explains regional variation in mane development. It is a model example of how a single trait can encode multiple messages to rivals and mates.