Environmental Enrichment Increases Brain Volume in Snakes.

The effects of environmental enrichment have been well documented in mammals and birds, but less work has focused on reptiles. Because snakes are common in captivity, both as pets and in research/commercial facilities, it is critical to explore how they react to standard captive housing. Here, we examined the effects of environmental enrichment on brain development in a popular pet snake species, the western hognose snake (Heterodon nasicus). Hognose snakes (n = 15) were individually housed for one year in either enriched or standard environments before their brains were harvested and imaged using MRI. We found that enriched snakes had significantly larger brain volumes compared to standard snakes, most prominently in posterior brain regions. In addition, we observed sex-specific brain investments: as snakes grew larger, males displayed relatively larger cerebral hemispheres, and females displayed larger posterior brain regions. These results suggest that environmental enrichment is critical to encouraging healthy brain development in snakes and that snake brain plasticity is very similar to that observed in mammals and birds.