Abstract: The inherent differences in composition and structure among milk sources may result in distinct gastrointestinal digestion behaviors and nutrient release profiles. A systematic evaluation of milk digestion characteristics may provide deeper insights into the nutritional value of different milks. In this study, seven milk sources, including human milk, monogastric animal milks (donkey and mare milk), and ruminant animal milks (cow, buffalo, sheep, and camel milk), were selected to investigate the similarities and differences in digestion behaviors and nutrient release patterns. During gastric digestion, donkey and mare milk exhibited relatively minor changes in particle size, while sheep milk showed intermediate particle size changes between monogastric animal milks and camel milk. In contrast, the particle sizes of cow and buffalo milk increased to 40.96±2.13 and 31.72±0.85 μm, respectively, accompanied by the formation of relatively dense protein curds. At the end of gastric digestion, the degrees of protein hydrolysis of human milk (2.34%±0.39%), donkey milk (1.60%±0.14%), and mare milk (2.26%±0.41%) were significantly higher than those of ruminant milks (P<0.05). After intestinal digestion, the final degrees of hydrolysis of human milk, donkey milk, and mare milk reached 25.87%±1.22%, 32.67±1.23%, and 29.08±3.09%, respectively, and remained significantly higher than those of ruminant milks (P<0.05). However, the amount and rate of free fatty acid (FFA) release from these milks were lower than those from ruminant milks. Human milk and monogastric animal milks exhibited higher FAA release per unit of protein. Principal component analysis further demonstrated that the FAA profiles and overall release patterns of digested donkey and mare milk were more similar to those of human milk, whereas ruminant milks showed relatively similar characteristics. Overall, monogastric animal milks exhibited digestive kinetics and nutrient release patterns more closely resembling those of human milk. This study provides insights into the gastrointestinal adaptability of different milk sources and contributes to the development of nutritional evaluation systems for milk products.