Primate natal coats: a preliminary analysis of distribution and function

Area of Science:

• Primate Ethology
• Evolutionary Biology
• Zoology

Background:

• Infant pelage coloration in primates has been observed to differ from adult coloration.
• Several hypotheses exist to explain the function of these distinct natal coats, including alloparental care, infant defense, and paternity cloak.

Purpose of the Study:

• To test existing and propose new functional hypotheses for primate natal coat coloration.
• To investigate the relationship between mating systems and infant coat contrast.
• To analyze the timing and pattern of natal coat changes in primate infants.

Main Methods:

• Compilation of pelage coloration data for infants across 138 primate species.
• Comparative analysis of neonatal versus adult pelage.
• Statistical assessment of the association between testes weight and natal coat contrast.

Main Results:

• Over half of the studied primate species exhibit neonatal pelage that contrasts with adult coloration, with inconspicuous contrast being more common than flamboyant.
• Natal coats are typically lost by 18 weeks postpartum, with the head and/or dorsum being the first areas to change.
• Functional analyses supported the infant defense and paternity cloak hypotheses, while refuting the alloparental hypothesis.

Conclusions:

• Primate natal coats likely serve functions related to infant defense and paternity assurance, potentially reducing infanticide.
• The study suggests natal coat contrast is categorically differentiated (inconspicuous vs. flamboyant) rather than a continuous gradation.
• A significant link exists between mating systems, indicated by testes weight, and the degree of natal coat contrast.