Recreational therapists' use of animal-assisted interventions (AAIs) with older adults is gaining popularity. However, no known research compares the effectiveness of canine- and equine-assisted therapies to a typical recreational therapy (RT) social intervention. This research, using an alternating treatment design, compared the participant's engagement, apathy, heart rate variability, and social responsiveness to equine, canine, and social interventions over five 2-hour sessions. Because identical protocols (grooming, leading, and feeding) were used, the variability in engagement, coherence, and social responsiveness likely relates to the different interventions. The participants' familiarity with a particular animal and the size of the animals may impact their reaction to AAI. Incorporating AAI in RT may decrease socialization-related apathy and improve engagement for older adults with dementia.