Interactive visualizations are increasingly emerging in science centers to communicate complex scientific ideas. Yet little is known about public engagement with exploranative exhibits combining explorative and explanative visualization. This study investigates visitors' engagement with the Marine Food Web, a touch-based 3D Antarctic food web exhibit about ecological relationships in the context of climate change. A mixed-method design combined five semi-structured interviews with log data from 995 science center visitor sessions. Qualitative analysis showed both sound scientific reasoning, for example about trophic relationships and population dynamics alongside misinterpretations, related to depth cues and node-link structures. Affective responses ranged from curiosity and aesthetic appreciation to climate concern. Usage constraints including graph auto-rotation, node density, and dual-screen split attention, might limit understanding. Quantitative analyses of exhibit log files revealed wide variation in engagement. Most visitors interacted briefly, while longer sessions (>5 min) featured extensive exploration of the food web, including increased page visits and interactions per session compared to shorter sessions. Our findings reveal novel benefits and challenges of exploranation for public engagement with complex science visualizations. We highlight the need for interaction control, decoding support, and alignment between narrative and interactive affordances, which may inform empirical guidance for future exploranative exhibit design.