Primate origins: Lessons from a neotropical marsupial

Area of Science:

• Evolutionary Biology
• Primatology
• Zoology

Background:

• The didelphid Caluromys displays convergent evolution with prosimians, exhibiting large brains, eyes, slow development, and agile locomotion.
• This convergence suggests analogous selection pressures to those driving early primate divergence from primitive ancestors.

Purpose of the Study:

• To test the arboreal, visual predation, and angiosperm exploitation hypotheses of primate origins using Caluromys as a model.
• To investigate the interdependent nature of these hypotheses in explaining primate evolution.

Main Methods:

• Quantitative data collection on free-ranging Caluromys derbianus in Costa Rica.
• Observational analysis of locomotion, foraging, and predatory behaviors.

Main Results:

• Caluromys derbianus is highly arboreal, engaging in visually directed predation for arthropod prey.
• Extensive terminal branch foraging on angiosperm products was observed, consistent with exploitation hypotheses.

Conclusions:

• The behaviors of Caluromys support all three major hypotheses of primate origins (arboreal, visual predation, angiosperm exploitation).
• These findings suggest the hypotheses are not mutually exclusive but rather interdependent factors in primate evolution.
• Exploitation of angiosperm products and insects in terminal branches, coupled with visually directed predation, likely played a key role in early primate divergence.