Enrichment, stimulation. | natural-iguana

What is enrichment?

Environmental enrichment or (EE) is sometimes called behavioural enrichment, this simply just translates to that it is exposure to a variety of stimulation or opportunities which encourage animals to perform their natural behaviour by engagement directly with their environment. This can involve species-suitable cognitive problem solving opportunities, openings and incitement, exposure to physical dimensions such as smell, taste, texture, touch, sound and vision. Environmental enrichment or EE incorporates the customary arrangement of physical situations, psychological difficulties, social and nutritional opportunities.

An improved domain throughout social media platforms seek to advance a scope of ordinary practices that our reptiles find compensating just as enabling to decidedly react to potential contacts and controlled stressors. For instance, chances to conceal or climb far from conspecifics or increasingly and more importantly fitness promotion in efforts to develop improvement in animal welfare.

There are five forms of EE typically recognised.

Sensory This category stimulates all of the animals’ senses- visual, olfactory (smell), auditory (hearing), taste and tactile (touch) senses.
Foraging/Feeding This is the manner by which guardians make sustaining time challenging and a good time for the creatures to explore foraging modes that they would naturally exploit. For example many herbivores are grazers so may graze moving from plant to plant eating different plant parts of different, ages, sizes, sexes, fruits and colours flowers of varying colour. Some carnivores or omnivorous animals may be required to hunt out and chase their food. Promotion of of errand arranged problem solving feeders and various techniques to encourage animals to think and work for their sustenance, as they would in nature.

3.Manipulative objects or/Toys These are objects and things that can be controlled here and there by means of hands, mouth, legs, horns or head and claws, basically for examination and exploratory play. A couple of precedents are: balls, boxes, packs and barrels, in some cases even other cuddly toys.

4. Environmental This class empowers pet guardians to dictate or to upgrade living space of animals with circumstances that change or add multifaceted nature to their condition. This is practiced through an assortment of novel substrates, swings, climbing structures, hiding areas/basking areas, and so forth.

5. Conduct/Social Social collaboration through preparing and organised play manufactures trust and affinity among guardian and creature. Chances to cooperate with different

creatures (even fake imitations or piñatas!) likewise animate valuable common practices and nature, or allowing territories to be established and allowing dominance interaction.

Historically, EE has not been given much focus in herpetoculture or in reptiles all that much in decades gone by except for in a few niche circles due to partially to our own limited understanding of these animals and how they behave in the wild all of the time, included in this blame is the difficulty (due in part to our mammalocentric bias) in accurately interpreting behaviours in animals so different to our own morphology, enrichment is often an area deemed psychological and thus has been avoided by mainstream science in reptiles until very recently due to the difficulties of measuring this. As a consequence now, with the development of new techniques and long term keeping welfare interest among private keepers and zoological collections, as well as an explosion of discussions within social media private pet keeper circles. It is a discussion which can be met, shared and understood by both scientist, vet and keeper.

Some studies have sought to experiment and better understand from physiological and psychological positions the effects of measurable welfare on the health, well being and longevity of this amazing group of misunderstood animals, the idea that they are dumb and mechanistic driven only by instinct is currently being challenged for the better.

For example, leopard geckos Eublepharis macularius have clearly demonstrated their hardiness over the years having been subject to the tupperware systems in which poor thermal, lighting gradients are able to be achieved, while simultaneously keeping them on paper towels or other substrata which inevitably has further restricted their normal and yet natural digging behaviour. In the past private keepers and breeders have argued that the geckos don't care, they seemingly still appear to feed and breed (something I myself have first hand had experience with in the past too, yet when this was put under the scientific lenses one study published by (Bashaw et al., 2019) has demonstrated that leopard geckos have, do and will respond to five kinds of enriched environmental stimulation and in beneficial ways. (Almli and Burghardt, 2006) demonstrated that rat snakes sp Elaphe housed in enriched exhibits habituate better than snakes housed laboratory/sterile and minimum conditions. (HOLTZMAN et al., 1999) has found that the commonly kept corn snake is adept at learning through experimental spatial mapping and orientation escape tasks. This study has clearly shown that snakes can learn more rapidly and is relevant behaviourally, the experiment explained that by entering a shelter it reinforces this learning, animals provided enriched settings, learned the escape maze task much faster when compared to an unenriched group. (Leal and Powell, 2011) also found that the sp Anolis evermanni is surprisingly proficient at problem solving which was surprising for the researchers as lizards have traditionally been viewed as having impaired cognitive abilities.

Iguanas are remarkable, magnificent and highly intelligent animals and unfortunately in many captive situations never receive the opportunities to exploit a full repertoire of their behaviours of engage their senses in captivity due to all to frequent sterile bare minimal approaches advocated on a somewhat larger scale. It is only the authors opinion that there is a multifaceted issue of poor research undertaken on the owners part in respect of this, and despite other areas of herpetological research being unertaken, little has been updated for iguanas, although we can extraporlate much of what is found may very well be transferable. There is new research becoming available all of the time and it is becoming difficult to keep up with it all.

Myths and misconceptions While it is clear husbandry styles and differences will exist based on differing husbandry preferences, geographic location, and life styles, there is currently unfortunately to a degree still some resistance against the movement towards implementing enrichment in these animals to better welfare, let alone provide a spacious, and controlled environment as it is supposed that these animals are purely instinct driven, naturalistic keepers are not exempt from anthropomorphising either so the stance in stereotype in regard to this are a bit tit for tat in my own experience and observations. Creating enriched spaces is just another husbandry preference (albeit) less shared and demonstrated, it is a common misconception that only semi naturalistic private keepers/guardians provide enrichment however too, while I certainly believe naturalistic is the best way to go in husbandry choice, (my own opinion based on the evidence I have seen) it is still possible to implement enrichment into these animals lives without having a big fancy fake rocked vivarium s well. The one thing I am sure we all agree on, as keepers who have often kept these animals for many years, we know they are way more intelligent than reptiles have traditionally been recognised for and the only intention of this write up is to provide ideas, relay some of the evidence and try to share it.

I mentioned earlier that one of the justifications racking style systems have perpetuated is the “eating and feeding rule” which has historically been used to justify health or happiness, this misconception exists still in in that good metrics of measuring welfare in the animals are if it is eating, pooping, shedding, and breeding.. While I don’t think it is always wise to disregard keeper instinct, it must consistently be reviewed as some revealing new evidence suggests that ideas proliferated from social network platforms in relation to this may not be the case with reptiles and we should be careful to not just depend on it. In my own rescue experience I have personally witnessed first hand sick and ill animals still attempting to reproduce and in some cases, just after moving a few hundred miles too, for example in the outlined photo below of my male Albus whom had low calcium levels and high uric acid as well as was in recovery from dehydration, malnourishment who was attempting to breed with another female.

In a more extreme example of the El Nino events which occur in species Amblyrhynchus cristatus the Galapagos Marine iguanas (Royalsocietypublishing.org, 2019) which are exposed to a high level of environmental stress to the extent many undergo starvation and shrink due to partially digesting their bones. “Traditionally, long-term elevations in corticosterone were thought to provide aid in survival, but four lines of converging evidence now suggest the opposite”. These iguanas to an extent may be capable of delaying the effect of stress by switching the response off in order to be able to cope better energetically for this time period. (Rubenstein and Wikelski, 2003) Approximately 70% of the population will die during this period sadly, 30% survives though, and later will go on to reproduce again, despite such a high stressful environmental pressures.

We now also know that stressors can be a main trigger for reptiles to reproduce in some instances (Moore and Jessop, 2003) which contradicts the traditional thought that it inhibits behaviours of such and therefore can be translated to a happy/healthy animal. Seemingly, this may in part explain why reptiles are proficient at breeding under stressful, unenriched, poor, environmental captive conditions too. (https://www.sciencedirect.com/science/article/pii/B978012374930710007X, 2011) We can not reliably use the metrics of breeding and feeding as a good measurement of welfare in captive situations, they can certainly be considered aspects of enrichment however they are only a small part of a larger picture in the whole scheme of things. c (sciencenordic.com, 2019) (Kalliokoski et al., 2012)

From my own keeping experience and research I have came to vastly appreciate that this impressive group of lizards are highly complicated with many behavioural quirks and triggers. Thus when designing enrichment plans we should look partially at how the lizard behaves in the wild and how some of this can safely be implemented in a species appropriate physical/psychological and promotion regime. The information herein is only based on my own research and keeping experiences with a focus on minimising known physical and environmental stressors or attempting to mitigate some of the effects our captive animals may be exposed too.

(Hanley and Stamps, 2002) demonstrate some interesting differences between social behaviour and blood parasites, following a two pronged approach to 4 experimental groups. The field study revealed behaviour, hormones and parasites in free-living juvenile male black iguanas showed a pattern of significantly lower levels of the primary stress glucocorticoid, corticosterone in Ctenosaura similis infected with either ticks or blood parasites than in uninfected lizards. Yet, they did show an increase in stress hormones when captured and put into captivity, and imposed unnatural situations on them.

More aggressive copulation attempts in highly stressed animals are not unique to iguanas either, Lacerta vivipara demonstrates evidence for a best-of-a-bad-job strategy in study by (Gonzalez-Jimena and Fitze, 2019) In another study (Lutterschmidt et al., 2009) found that elevated levels of the stress hormone cortiocosterone did not have an impact on-reproduction in rattle snakes for example...

Going back to basics!

Thermal Importance and its implications in enrichment, updating discussion relating to temperatures.

Reptiles are ectothermic which simply just translates to (cold blooded). This just means reptiles have evolved to become primarily depend on external sources of heat (which is strongly associated with light intensity) energy in order to function at the most basic level. Not only is thermal input responsible for facilitating metabolic heat, digestion, locomotion and activity to or away from resources, it allows for a range of behaviours including, predator avoidance, aggression reproduction, and social play outs among conspecifics, but less discussed also helps with disease resistance implicating immune response. Basking is the most obvious sign associated with this, movement or advancing towards warmth and cooler areas - isn't only the most basic thing every owner can provide but it is also the least difficult in modern times.. (Cosquieri 2019) Accordingly, this has been argued to be the strongest type of enrichment for any reptile species. The explanation behind this is profoundly associated with how reptiles work and move. Each specie has their very own Tp (favoured temperature). But, the issue with accepting this value as a stable source of heat under captive conditions is comprehending what this favoured temperature is, because Tp can shift throughout the day time between different sexes at various occasions of year, at various ages, when foraging and yes, also throughout reproduction and daily activities (territorial patrolling etc)

(Vitt and Caldwell 2014) Outline some thermal ranges reptiles exploit irrespective of most commonly kept species or types.

For example. A green iguana may wake up early in the morning, in my experience they do this about half an hour before the lights go on. In the wild they move to the outer edge of the tree branches where they may position themselves perpendicular or (paralell) to the direction of where the sun rises, extension of the dewlap occurs, which acts somewhat as a solar panel. Within this thin flap of skin are blood vessels,, causing heat to radiate energy and is absorbed through the dewlap which in turn starts warming the blood vessels within, the blood is then pumped around the body by the heart, thus somewhat warming the core temperatures of the lizard as well as the external temperatures across the body. At the same time, these lizards are capable of altering colouration in order to be able to absorb or pull more heat to the skin, or to reflect it, this is called conduction and convection through radiation, (I have only seen this behaviour under outdoor conditions) this simple but marvellous adaption, simply works on the principle, that darker colours will conduct heat, (similar to us wearing a black t-shirt on a hot day) and convection, which means altering the colour to a lighter shade will help reflect some of the heat away.

Once the iguana has achieved a desired temperature, it may move more into the interior of the tree branches or vegetation in order to feed, or graze, meaning a different temperature will be intercepted both from the shaded tree trunks, and from the drop in ambient temperature. If at any point, the lizard feels threatened, it may invoke tonic immobility (Greene et al., 1978), or simply drop off the tree perch into a nearby water source, exposing it to a very different range of temperatures, meaning, it must again resurface in time and warm itself back up.

If this iguana however carries stripes, or natural dark spots or stripes, this too, may have implications on the effectiveness between heat exchange from environment to body both through radiance and thigmothermy. An iguana, on the ground, as can be observed in my female iguana here, is partially exposed to light, and shade at various locations due to the gaps between the leaves. She is of course, intercepting a delicious leaf of slender leaf of plantain in the orchard, but for this few seconds, she is exposed to a very different set of temperature to what she was basking in only a moment before hand. Showing that her preferred temperature at that moment in time has shifted.

This microclimate is based on something called LAD (leaf area density) and leaf scatter illumination. Many tree dwelling lizards use this both on the ground and in the trees. (Seigel and Collins, 1993)

Downpour of rain, may also influence temperature variable, as well as wind, and other weather behaviour, therefore, temperature fluctuation, likely has an impact on locomotive and thermal decision makers of the lizard too.

The wild animal is quite active, and thermal implications exist primarily toward behavioural decision makers which will largely be temperature dependent. As we can see, exposure to a wide variety of temperatures likely exists for our scaly companions.

As I am sure we all know, Iguanids are diurnal (active during the day) sun lovers, termed heliotheric species, or heliotherms, (Avery RA. C Gans. 1982) meaning they depend heavily upon external sources of warmth naturally to warm up. (Primarily through the sun) They are poikilothermic, or poikilotherms which simply just means they are capable of behaviourally deciding which temperature ranges to intercept and when. Bradymetabolic, meaning they have a lower resting metabolism at low temperatures. Thigmothermic translates to gaining heat directly from contact with a physical object, (belly heat) (Library.iucn-isg.org, 2019)

The thermal complexity of environments in which these animals naturally live has often gone under appreciated in herpetocultural literature, in the interchange between a range of temperature shifts it makes this difficult to offer a one size fits all answer for all species and even all individuals within a species but I myself try to focus on the voluntary minimum and maximum temperatures a species orients towards through my own keeping observations and research. A reptile's favoured temperature does not for the most part always mean it is the ideal temperature for all of its natural bio performances yet we should begin to look at it as they are dependent upon a range of temperatures to exploit them all (Vitt and Caldwell, 2014) other factors can influence it and how the reptile thermoregulates, and finally we should consider where it decides to thermoregulate. (In the tree canopies. Iguana iguana, or in more fossorial or terrestrial sp Dipsosaurus dorsalis for example. In the interchange between this, arboreal species may surface to the ground on certain occasions, and fossorial or terrestrial species may seek higher elevations upon rocks or lowland shrubs in certain situations.

Most reptiles move along a surface or varying elevations of perch sights at different times of the day. They may withdraw from warmth at certain occasions, and search it out at others. Offering them an increase in choice for intercepting different temperature ranges is the whole point of recreating a thermal gradient in captivity, and applying wild values observed in natural history into our enclosures.Traditionally much iguana iguana literature suggests that a basking temperature of between 30-35c or 86-95f is optimal for this species, commonly termed POTZ (preferred optimum temperature zone) with the lower end capable of facilitating digestion also.