Evaluating Environmental Enrichment Methods in Three Zoo-Housed Varanidae Lizard Species

James O Waterman,Andrea L Fidgett,Rachel Mcnally,Matthew Cook,Lisa Holmes,Daniel Harrold,Gerardo Garcia

doi:10.3390/jzbg2040051

Abstract

Environmental enrichment has been shown to enhance the behavioural repertoire and reduce the occurrence of abnormal behaviours, particularly in zoo-housed mammals. However, evidence of its effectiveness in reptiles is lacking. Previously, it was believed that reptiles lacked the cognitive sophistication to benefit from enrichment provision, but studies have demonstrated instances of improved longevity, physical condition and problem-solving behaviour as a result of enhancing husbandry routines. In this study, we evaluate the effectiveness of food- and scent-based enrichment for three varanid species (Komodo dragon, emerald tree monitor lizard and crocodile monitor). Scent piles, scent trails and hanging feeders resulted in a significant increase in exploratory behaviour, with engagement diminishing ≤330 min post provision. The provision of food- versus scent-based enrichment did not result in differences in enrichment engagement across the three species, suggesting that scent is just as effective in increasing natural behaviours. Enhancing the environment in which zoo animals reside is important for their health and wellbeing and also provides visitors with the opportunity to observe naturalistic behaviours. For little known and understudied species such as varanids, evidence of successful (and even unsuccessful) husbandry and management practice is vital for advancing best practice in the zoo industry.

Highlights

Environmental enrichment is used to improve the health and welfare of species managed ex situ, one desired outcome of which is the broadening of an individual’s behavioural repertoire [1]
We examine the behavioural responses to enrichment of three Southeast Asian varanid species held at Chester Zoo, UK: Komodo dragons (Varanus komodoensis), emerald tree monitors (V. prasinus) and crocodile monitors (V. salvadorii)
Post-hoc testing revealed that the food (Tukey HSD; P = 0.008), scent (Tukey HSD; p < 0.001), and scent (Tukey HSD; p < 0.0001) conditions were all associated with significant increases in exploratory behaviour (Figure 1a)

Summary

Introduction

Environmental enrichment (referred to as enrichment hereafter) is used to improve the health and welfare of species managed ex situ, one desired outcome of which is the broadening of an individual’s behavioural repertoire [1]. Reptile enrichment methods have historically been based on the anecdotal evidence of caregivers, often drawn from experience with a limited group of individuals [2,3]. Two key points may account for this gap in our knowledge: (1) evaluating the welfare of reptiles is challenging [6] and/or (2) the cognitive sophistication of non-avian reptiles is often under-estimated ( compared to that of mammals and birds [8,11,12]).

Methods

Results

Conclusion