Does a bigger terrarium reduce a green anole's stress? What a study shows
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
"Get the biggest terrarium you can" is common advice given to prospective green anole owners. A Belgian team tested that intuition by directly measuring physiological stress markers across different terrarium volumes. Our other habitat guidance for this species is in the bedding & habitat section, with the full care sheet on the green anole.
Contents · 4 sections
A range of volumes tested under the same protocol
Borgmans, Palme, Sannen, Vervaecke and Van Damme published a study in 2019, in the journal Animal Welfare, comparing green anoles (Anolis carolinensis) housed in terraria of different sizes, ranging from 0.05 to 0.2 m³ in volume (see the study). The researchers tracked several indicators in these animals: body mass, tail-base width, heterophil-to-lymphocyte ratio (a blood marker of stress), observed behavior, and fecal corticosterone metabolites.
No measurable effect detected within that range
Across all these markers, the study found no significant effect of terrarium volume within the tested range. In other words, between the smallest and largest terrarium in the sample, neither body weight, nor behavior, nor the stress hormones measured in droppings varied detectably. A result that runs counter to the assumption that doubling or tripling enclosure volume mechanically improves an animal's physiological welfare, at least on the criteria measured here.
What this result doesn't say
This lack of effect doesn't mean terrarium size is irrelevant in every respect: the study doesn't test volumes below recommended welfare standards, and it doesn't measure behavioral dimensions like room to move, access to a properly staged thermal gradient, or the ability to escape a cage-mate in cohabitation. Those needs remain documented elsewhere, notably in our guidance on green anole terrarium size and setup. What the study shows, precisely, is that within an already adequate range, making the terrarium bigger still didn't improve the stress markers measured.
What this means for buying a terrarium
For a green anole already housed in a reasonably sized terrarium, this result suggests putting the budget toward other levers rather than an ever-larger volume: UVB lighting quality, a well-tuned thermal gradient, stable humidity and vertical layout — factors this study didn't isolate, but which the broader literature on the species identifies as more consistently important day to day.
Should a large terrarium still be preferred for a green anole?
An adequate volume is still recommended for the species' behavior and living space; this study only indicates that beyond a certain point, going bigger didn't reduce the measured hormonal stress.
See it in the Planète Pets shop: Stick-on digital thermometer for aquarium and terrarium glass (€18.90) · the whole shop
This guide is part of Planète Pets’s Reptiles universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.
