Social structure and habitat design affect the impact of a novel feeding enrichment for alligators.

Providing enrichment that expands the range of behavioral opportunities associated with food acquisition and environmental exploration is an important contributing factor to the well-being of zoo animals. These behaviors can be difficult to promote in carnivores, given their foraging strategies and the logistical, ethical, and financial challenges of providing live prey. In this study, we introduced a novel feeding enrichment to Jacksonville Zoo and Gardens' five adult American alligators (Alligator mississippiensis) in an attempt to simulate a live prey organism within the exhibit and promote natural hunting behaviors like chasing and lunging, as well as increase daily activity levels. The enrichment promoted some behavioral goals for two of the alligators, but it did not promote behavioral goals for the other three alligators. This could have been due to a variety of factors including an existing dominance hierarchy amongst the group's females and the resulting spatial distribution of individuals across a habitat with only one water feature. Our results suggest that female alligators may carve out territories and avoid overlapping space usage with other females during the warmest months of the year. Given the outcomes and limitations of this enrichment strategy, we provide recommendations for this group specifically as well as future enrichment efforts in the general captive crocodilian population.

American alligator (Alligator mississippiensis) weight gain in captivity and implications for captive reptile body condition.

The body condition of an animal is an indicator of health status and is dependent upon many factors, some of which can vary between wild and captive settings. Despite this, there have not been many studies on how captivity affects body condition relative to wild animal populations. This study explores the body condition of captive and wild American alligators (Alligator mississippiensis) because reptiles are frequently overlooked in studies of captive animal health and because alligators are well-represented in captivity. We collected body condition data from 209 captive alligators and 935 wild alligators throughout Florida and southeastern Georgia and compared the relationships between body condition and body length for each group. We found that captive alligators exhibited significantly higher body condition values as they aged, and that this result was driven by the difference between captive and wild males. Body condition values for captive juveniles did not differ from wild juveniles, but they differed when comparing adults. Our results suggest that factors such as diet and movement rates play major roles in determining alligator body condition and that body condition may be an important metric for monitoring captive alligator health, especially for older adult males.

Getting It Straight: Accommodating Rectilinear Behavior in Captive Snakes-A Review of Recommendations and Their Evidence Base.

Snakes are sentient animals and should be subject to the accepted general welfare principles of other species. However, they are also the only vertebrates commonly housed in conditions that prevent them from adopting rectilinear behavior (ability to fully stretch out). To assess the evidence bases for historical and current guidance on snake spatial considerations, we conducted a literature search and review regarding recommendations consistent with or specifying ≥1 × and <1 × snake length enclosure size. We identified 65 publications referring to snake enclosure sizes, which were separated into three categories: peer-reviewed literature (article or chapter appearing in a peer-reviewed journal or book, n = 31), grey literature (government or other report or scientific letter, n = 18), and opaque literature (non-scientifically indexed reports, care sheets, articles, husbandry books, website or other information for which originating source is not based on scientific evidence or where scientific evidence was not provided, n = 16). We found that recommendations suggesting enclosure sizes shorter than the snakes were based entirely on decades-old 'rule of thumb' practices that were unsupported by scientific evidence. In contrast, recommendations suggesting enclosure sizes that allowed snakes to fully stretch utilized scientific evidence and considerations of animal welfare. Providing snakes with enclosures that enable them to fully stretch does not suggest that so doing allows adequate space for all necessary normal and important considerations. However, such enclosures are vital to allow for a limited number of essential welfare-associated behaviors, of which rectilinear posturing is one, making them absolute minimum facilities even for short-term housing.