Effect of bone strain on cortical bone structure in macaques (Macaca mulatta)

Area of Science:

• Primate biology
• Skeletal biology
• Functional morphology

Background:

• Food consistency impacts mandibular bone strain during mastication.
• Understanding dietary effects on bone structure is crucial for evolutionary and biomechanical studies.

Purpose of the Study:

• To investigate the effects of hard versus soft diets on mandibular bone histology and morphology in rhesus macaques.
• To determine if observed mandibular changes are adaptive responses to dietary mechanical stress.

Main Methods:

• Two groups of rhesus macaques were fed either a hard biscuit diet or a soft fudge-like diet.
• Mandibular and fibular bone samples were analyzed for secondary Haversian bone (remodeling).
• Mandibular depth and fibular diameter were measured and compared between groups.

Main Results:

• Monkeys on the hard diet exhibited significantly higher mandibular bone remodeling.
• The hard-diet group also showed increased mandibular depth at M2.
• Fibular morphology and remodeling remained comparable between the two dietary groups.

Conclusions:

• Increased mandibular remodeling and depth in hard-diet monkeys indicate an adaptive response to mechanical stress from mastication.
• The mandible's structure appears to adapt to the demands of processing hard foods.
• The fibula, not directly involved in mastication, did not show similar adaptive changes.