Study Says Leopard Geckos Prefer Bioactive Enclosures

[Homebody]

This is a link to a Reptiles magazine article about a study that shows Leopard Geckos prefer bioactive enclosures: https://reptilesmagazine.com/study-s...oogle_vignette. I thought it was clever how they measured the geckos' preferences, though the results were somewhat equivocal. It's tough to reach statistically significant results when you're only testing six specimens.

[Lord Sorril]

This is a link to a Reptiles magazine article about a study that shows Leopard Geckos prefer bioactive enclosures: https://reptilesmagazine.com/study-s...oogle_vignette. I thought it was clever how they measured the geckos' preferences, though the results were somewhat equivocal. It's tough to reach statistically significant results when you're only testing six specimens.

Performing behavioral research (correctly) is really difficult. It was a good attempt for someone.

[Malum Argenteum]

Interesting study, but has a couple fatal flaws for inferring anything about "bioactive" enclosures (which of course was not the point of the study, though lots of hobby keepers are going to incorrectly think it was).

For one, the different test conditions had their variables all mixed up. They didn't differentiate between typical hobby categories of 'standard' (basic plastic furnishings), 'naturalistic' (using natural materials such as sand/soil substrate, wood hardscape, and maybe live plants, and maybe UVB), and 'bioactive' (which is naturalistic + waste management via living organisms, and usually includes UVB). But of course, they were only testing two enrichment categories, not "bioactive" vs other relevantly similar setups.

They did differentiate between a basic enclosure with plastic furnishings and a complex enclosure with plastic furnishings, and they found basically that the leos glass surfed less. That's already known, I think. I'm not sure that soaking in the water bowl is a positive sign, though, so the observations here are somewhat questionable.

Another questionable set of observations is that "there was more time [...] spent in the top half of the enclosure in the Enriched conditions". Since there were only cage furnishings in the top half of the enclosure in the 'enriched' condition and not in the 'standard' conditions, nothing can be extrapolated from those observations except that leos won't climb much if there's nothing for them to climb on (which should be obvious).

They "observed no differences in behavioural expression between the Naturalistic and Non-Naturalistic enriched enclosures", which entails that live plants and microfauna do not change leos' behavior vs plastic plants and no microfauna. That's a surprising result to me, but it certainly undermines a support for hobby 'bioactive' enclosures (since the study shows you can get the same behavioral results from plastic plants and no bugs).

They also, very importantly, didn't measure or test for effects correlated to humidity (which should be expected to be higher in their 'naturalistic enriched' category). Leos are very typically kept in captive environments that have less humidity and overall moisture than they're known to prefer in the wild (published observations state that they don't come out of hiding unless RH is above something like 50%). The increased moisture in the 'naturalistic enriched' enclosure may well be sufficient to explain the preference, rather than the other elements of that enclosure.

This (namely, that moisture is the important variable in the 'naturalistic enriched' category) is further supported by the observation that in the 'non-naturalistic enriched' condition the leos were observed soaking in their water bowl; I'd submit that the two conditions without live plants had insufficient RH, and only in the conditions where there was enough clutter for the leos to feel safe being out in the open in a water bowl -- a bizarre behavior itself -- were the leos able to do something to avoid the dryness.

Since they didn't test the hobby categories of 'bioactive' against that of 'naturalistic', and failed to control for obvious variables, it is unwarranted to claim that this study shows that "leopard geckos prefer bioactive enclosures". The experiment simply was not set up to test that condition. Nothing about the study supports the use of UVB (which is a very common part of "bioactive" care), nor microfauna or live plants (except as factors that motivate an increase RH and substrate moisture, which is simple enough to do with a spray bottle).

[Bogertophis]

I think you nailed it again, Malum. ^ ^ ^ It's been a long while since I had a Leo, but I've sure never seen one soaking in their water bowl- I agree that this article is likely to lead readers to misinterpret the article as showing that bioactive is preferred, which surely won't disappoint those advertisers in Reptiles magazine that are selling bioactive supplies.

[Malum Argenteum]

Yeah, a little poking around suggests that most of the study authors are general animal behaviorists, so wouldn't necessarily clue in to the important details. The lead author is a PhD candidate studying "how captive enclosures can holistically affect animals, with a significant emphasis on naturalistic (bioactive) enclosure conditions", though, and really should know better. Seems there's some bias and not a little sloppiness in that passage, which is worrying from a scientific point of view.

Relatedly, if you look at the sketches of the enclosure layout and hardscape it is clear that even the 'naturalistic' enclosure isn't at all naturalistic from the POV of Eublepharis macularius -- leos exploit the space behind tree bark, and crevices between and under rocks and building foundations, not rope ladders and hollowed coconuts.

"likely to lead readers to misinterpret the article as showing that bioactive is preferred" -- yes. The specific problem is that the study shows that bioactive is preferred over housing that's substandard in ways that have nothing to do with specifically "bioactive" factors, so it is a conclusion that's reached fallaciously. I could design a study that shows that children prefer tofu burgers over other food -- just make the other food be chili peppers and asparagus -- and the tofu fanatics would say that I showed that children prefer tofu. More specific, better designed and better controlled research, along with a rich baseline understanding of the species under study, is what we need to get good data.

Coming in from another angle, we need to be skillful readers/interpreters, too. Studies might show that leopard geckos prefer waxworms, but that's of course not tantamount to a recommendation that leos be fed waxworms; my doctor seems never to recommend the things that I prefer, but I don't think that makes me correct and him wrong. But in this study the authors found that leos prefer enclosures that happen to be "bioactive" and leapt right to recommending that leos be kept in bioactive enclosures. This recommendation doesn't follow from the data (and recommendations in scientific studies -- 'you ought to...' -- are very problematic in general since science uncovers facts, not evaluations). Recommendations (for anything in life) need to follow from a careful consideration of all the relevant factors, not only from observations that the thing being recommended is preferred over a couple other options.

[Bogertophis]

... Eublepharis macularius -- leos exploit the space behind tree bark, and crevices between and under rocks and building foundations, not rope ladders and hollowed coconuts..."


"likely to lead readers to misinterpret the article as showing that bioactive is preferred" -- yes. The specific problem is that the study shows that bioactive is preferred over housing that's substandard in ways that have nothing to do with specifically "bioactive" factors, so it is a conclusion that's reached fallaciously. I could design a study that shows that children prefer tofu burgers over other food -- just make the other food be chili peppers and asparagus -- and the tofu fanatics would say that I showed that children prefer tofu. More specific, better designed and better controlled research, along with a rich baseline understanding of the species under study, is what we need to get good data.

Coming in from another angle, we need to be skillful readers/interpreters, too. Studies might show that leopard geckos prefer waxworms, but that's of course not tantamount to a recommendation that leos be fed waxworms;....

Exactly- all of this ^. Critical thinking, folks...with a healthy dose of skepticism. And always "follow the money" (who's funding the research?).