Dolphin Interleukin-13 (IL-13) is a Th2-associated cytokine produced primarily by activated CD4⁺ T helper cells and other type 2 immune populations in dolphins, particularly the bottlenose dolphin (Tursiops truncatus), where it plays a role in regulating mucosal immunity, alternative macrophage activation, and tissue remodeling. IL-13 signals through receptor complexes containing IL-13Rα1 and IL-4Rα, activating JAK/STAT6 pathways that modulate gene expression involved in IgE-associated responses, mucus production, suppression of pro-inflammatory cytokines, and promotion of wound healing. In dolphin health, IL-13 may be particularly relevant in responses to parasitic infections, chronic dermatitis, respiratory disease, and tissue repair following injury, where balanced type 2 immune responses help limit tissue damage while supporting recovery. Dysregulated IL-13 expression could contribute to fibrosis or chronic inflammatory conditions, especially in the context of environmental stressors such as pollutant exposure or harmful algal blooms. As dolphins serve as sentinel species for marine ecosystem health, IL-13 represents an important biomarker of Th2 immune polarization and inflammatory regulation in both managed and wild populations. Characterization of dolphin IL-13 supports studies of host–pathogen interactions, immune adaptation to marine environments, and comparative type 2 immune mechanisms relevant to both wildlife conservation and broader mammalian immunology.