Animal Welfare

Scientific Papers

Red Ibis

© Rory Harper

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Do zoo-housed primates retreat from crowds? A simple study of five primate species(Cairo-Evans et al., 2022)

July 2022

A paper in the American Journal of Primatology investigated whether five zoo-housed primate species retreated with an increase in visitor numbers:
Allen's swamp monkeys, eastern black-and-white colobus monkeys, Bolivian gray titi monkeys, DeBrazza's monkeys & crowned lemurs;
Animals did not retreat as visitor numbers increased;
Small but statistically significant decrease in distance with increasing visitor numbers;
Behavioural welfare indicators unaffected by number of visitors;
Proximity to visitors may be a useful indicator for welfare assessments.

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Is Chimpanzee (Pan troglodytes) Wounding Frequency Affected by the Presence Versus Absence of Visitors? A Multi-Institutional Study (Salak & Barbour, 2022)

July 2022

Does the presence or absence of visitors have an effect on captive chimpanzee wounding? A study in JZBG looked into it:
 21 chimpanzees across 3 zoos;
 Frequency of "no wound" events compared in the presence and total absence of visitors;
 Frequencies were similar across conditions, suggesting presence of visitors did not influence wounding behaviour.

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Examining how a general audience rates herptile welfare in zoos (Devlin & Ogle, 2022)

March 2022

How do zoo visitors perceive reptile & amphibian welfare? A study in JZAR looked into it:
✔ Perceptions of herptile welfare influenced by comfort level with animal,  its perceived likeability & previous experiences with the animal;
✔ Number of annual visits to the zoo can also influence perceptions;
✔ Visitors ranked size of enclosure lower than other welfare objectives - preference for larger enclosures?
✔ Visitors perceive zoos are meeting physical needs of herptiles but can improve in meeting their affective needs.

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Location, Location, Location! Evaluating Space Use of Captive Aquatic Species—A Case Study with Elasmobranchs
(Hart, Reynolds & Troxell-Smith, 2022)

June 2022

The space use of five captive elasmobranch species was evaluated in a new study in JZBG:
✔ Enclosure divided in five sections: Exhibit use (X-Y axis) and Depth use (Z axis);
✔ Despite differences between individuals, Exhibit use was relatively even, while Depth use was uneven.
✔ Results as expected according to each species' natural history, except for the smooth dogfish, which required further interventions;
✔ Space use can be a valuable tool in animal welfare assessments.

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Behaviour of Zoo-Housed Red Pandas (Ailurus fulgens): A Case-Study Testing the Behavioural Variety Indexs
(Spiezio et al., 2022)

May 2022

The behaviour of two zoo-housed pairs of red pandas was studied in a paper published in JZBG...
No abnormal behaviours reported; 
Time budgets similar to those reported for the species;
Resting, comfort & vigilance behaviours most frequent;
Behavioural Variety Index (BVI) showed each animal performed approximately 73% of behaviours described for the species.
BVI may be a useful tool for animal welfare assessments & behavioural studies.

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Bird Welfare in Zoos and Aquariums: General Insights across Industries (Woods, Eyer & Miller, 2022)

May 2022

A review on bird welfare in zoos and aquariums has been published in JZBG:

✔ Bird welfare research can be informed by research from other industries;
✔ More research on a wider range of bird species & research topics recommended.

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Does Handling for Public Talks in Zoos Affect the Behaviour of Captive Mexican Red-Kneed Spiders Brachypelma hamorii?(Gresham et al., 2022)

April 2022

In a study in JZBG, the behaviour of zoo-housed Mexican red kneed spiders was monitored in the 24 hours after handling for education sessions:
✔ Time spent under-cover & in limb-interaction behaviour higher on handling days;

✔ Handling significantly affected behaviour - more research needed to determine welfare implications;
✔ Protocols for the handling of invertebrates in education sessions should be developed and/or refined.

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Social Behavior Deficiencies in Captive American Alligators (Alligator mississippiensis(Walsh et al., 2022)

March 2022

A comparison of social behaviours between free-living and captive American alligators was published in JZBG:
Frequency of social behaviours was much higher in the wild congregation;
Wild congregation also showed a richer social behavioural repertoire;
"High walking" - a non-social behaviour & potential stereotypy - was most frequent in the captive congregation;  
"Flushing" was used as a defense reaction to human disturbance in both congregations.

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From left to right all through the night: Characteristics of lying rest in zoo elephants (Schiffmann et al., 2022)

April 2022

An investigation into lying rest behaviour of zoo-housed elephants was published in Zoo Biology:
 Longer lying durations in elephants housed on soft substrates;
 Dominance status also affected lying rest;
 Higher frequency of side changes between lying bouts on soft substrates;
 Soft substrates & healthy social environments seem to improve lying rest behaviours & welfare.

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Differing animal welfare conceptions and what they mean for the future of zoos and aquariums, insights from an animal welfare audit (Veasey, 2022)

March 2022

A recent study, published in Zoo Biology, compared animal welfare conceptions between animal caretakers, visitors & veterinary staff:
 Strong correlation between the animal carers' holistic welfare assessments & the visitor perceptions of animal happiness;
✔ These assessments did, however, inversely correlate with the assessments by the veterinary staff;
 Visitor perceptions of animal happiness strongly correlated with their enjoyment of zoo visits; 
 Clarification of animal welfare concepts among zoo staff is recommended;
 Improving animal welfare also benefits the visitor experience & therefore the zoo's commercial aims.

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Impacts of Socialization on Bull Asian Elephant (Elephas maximus) Stereotypical Behavior (Readyhough et al., 2022)

March 2022

The effects of social housing on the stereotypical behaviour of bull Asian elephants were investigated in a study published in JZBG:

 Decrease in stereotypies (both pacing & head bobbing) when housed with at least other elephant;

 Decrease in stereotypies as affiliative behaviours increased while agonistic behaviour had no effect;

 Pacing was higher when lone bulls were in musth;

 Social housing may improve welfare of bull Asian elephants in captivity.

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Preliminary investigation of the effects of a concert on the behavior of zoo animals (Harley et al., 2022)

February 2022

A preliminary study published in Zoo Biology investigated if and how several zoo animals were impacted by a concert:
Some species showed behavioural changes correlated with the event (mostly associated with active & resting behaviours);
No behavioural changes detected in several species;
Differences between species highlights need to monitor behaviour during events & to consider each species natural biology when trying to mitigate their effects;

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Do Birds of a Feather Always Flock Together? Assessing Differences in Group and Individual Zoo Enclosure Usage by Comparing Commonly Available Methods (McConnell et al., 2022)

February 2022

A paper in JZBG compared enclosure use in zoo-housed flamingos using data collected at group- and individual-level:

Overall preferred zone occupancy was similar between methods;

Individual data showed wider use of enclosure than group data;

Individual data suggested zone underuse, while group data suggested zone overuse;

Both methods should be used for more accurate assessments of enclosure use and welfare.

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The effects of Zoo Lights on animal welfare: A case study of great Indian hornbills at Denver Zoo (Readyhough et al., 2022)

January 2022

A paper in Zoo Biology looked into the potential effects of Denver Zoo's "Zoo Lights" evening event on the behaviour and welfare of the great Indian hornbills in their care:

No significant increase in aggressive behaviour during or after the event;

Affiliative behaviours increased, but likely because it coincided with breeding season and not because of the event;

Applications to zoo management.

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Feasibility and validity of the Animal Welfare Assessment Grid to monitor the welfare of zoo-housed gorillas Gorilla gorilla gorilla
(Brouwers & Duchateau, 2021)

October 2021

A study in JZAR evaluated a gorilla welfare assessment tool based on keeper ratings:

Welfare of two groups of zoo-housed gorillas monitored daily for three months (keeper ratings and behavioural observations)

Keepers detected more subtle changes in welfare than researchers in previous studies;

Despite good inter-rater reliability, keeper scores did not always match behavioural observations - more training, staff meetings & longer observations recommended.

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Evaluating physiological and behavioural responses to social changes and construction in two zoo-housed female giraffes
(Jain, Santymire & Wark, 2021)

October 2021

A paper in JZAR described the physiological (faecal glucocorticoid metabolites - FGMs) & behavioural responses of two zoo-housed giraffes to construction work:
Higher FGMs in both giraffes during initial demolition phase;
One individual also showed higher FGMs, decreased inactivity and increased stereotypies during active construction phase,
One of the giraffes became ill and was euthanised, which caused changes in the behaviour & physiology of the other one;
Construction work and loss of social partner were sources of stress - applications to giraffe management.

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Behavior and Habitat Use Remain Diverse and Variable in Modern Zoological Exhibits over the Long-Term: Case Studies in 5 Species of Ursidae (Powell & Baskir, 2021)

December 2021

A paper in JZBG investigated behaviour & habitat use in zoo-housed bears over multi-year periods:

2 zoos, 5 species, 9 individuals;

Activity budgets diverse & dynamic over time (more so in younger individuals);

Habitat use decreased over time;

Changes in behaviour associated with decreased welfare likely related with age or seasonality rather than habitat;

Changes associated with positive welfare observed - frequent daily variation in behaviour & rare stereotypies;

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Prevalence of regurgitation and reingestion and occurrence of coprophagy in the North American AZA Gorilla (Gorilla gorilla gorilla) population (Tennant et al., 2021)

November 2021

A paper in Zoo Biology investigated regurgitation & reingestion (R/R) and coprophagy behaviours in the gorilla North American (captive) population:
Survey competed by all AZA-accredited institutions with gorillas in their collection;
60% of population engages in R/R to some degree;
24% engages in coprophagy on a weekly basis;
Future research should focus on identifying drivers of these behaviours, so evidence-based actions can be taken to mitigate them.

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Costs and benefits of living in a vegetated, compared with non-vegetated, enclosure in male Japanese macaques (Macaca fuscata(Alejandro, Huffman & Bercovitch, 2021)

November 2021

A study in Zoo Biology investigated differences in the behaviour of Japanese macaques in a vegetated and in a non-vegetated enclosure:

Vegetated: Better coat conditions, more social play and feeding-related behaviours, less resting;

Non-vegetated: More stereotypic behaviours & agonistic interactions;

Findings suggest better welfare in vegetated enclosure, highlighting importance of recreating some features of natural habitat.

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Does enclosure size influence the behaviour & welfare of captive snakes (Pantherophis guttatus)? (Hoehfurtner et al., 2021)

October 2021

A new paper in Applied Animal Behaviour Science investigated the impact of enclosure size on corn snake behaviour and welfare:

Snakes more active in a large enclosure (longer than snake length) than in a small enclosure (2/3 of snake length);

Snakes stretched out in the large enclosure, spending almost 20% of resting time in this position (no opportunity for this behaviour in small enclosure);

"Loosely coiled" posture significantly higher in large enclosure;

Preference tests: active snakes preferred large enclosure;

Enclosure longer than snake length is recommended to improve behaviour and welfare of captive corn snakes.

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Photo: Exmor Zoo

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Behavioural Responses to Temporary Separation of a Captive Herd of African Elephants (Loxodonta africana
(Armstrong & Johnson, 2021)

September 2021

A study in JZBG investigated the behavioural responses of two captive female African elephants to temporary separation from other two herd members as they were being transported to other zoo:

Elephants travelled to the other zoo in two pairs: a mother-daughter pair & and an unrelated but bonded pair of females (short gap between transports);

The mother-daughter pair showed an increase in human-audible vocalisations, temporal gland secretions & decrease in play behaviour when the other pair left ahead of them;

Despite being mostly unrelated, the group showed similar signs of stress as expected if the group was highly related;

Applications to elephant management.

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Towards understanding the welfare of cetaceans in accredited zoos and aquariums (Lauderdale et al., 2021)

August 2021

Last week we shared the news that the results of the largest-ever captive cetacean welfare study were out... Here is an overview of their findings, published in Plos One:

Four species: Common & Indo-Pacific bottlenose dolphins, beluga whale & Pacific white-sided dolphin;

Data collected at 43 institutions between 2018 and 2019;

Reference values established for blood variables and fecal hormone metabolites available in app ZooPhysioTrak;

Enrichment & social management showed higher impact on welfare than habitat characteristics;

Applications to cetacean management & welfare in captivity.

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Using individual-specific conditioning to reduce stereotypic behaviours: A study on smooth dogfish Mustelus canis in captivity (Hart, Reynolds & Troxell-Smith, 2021)

July 2021

A study in JZAR discussed the impact of two interventions (relocation to a less dynamic pool & individualised feeding & conditioning method) on the behaviour of a captive female smooth dogfish:

Reduction of stereotypic behaviours after interventions;

Increase in species-specific & resting behaviours;

Increase in enclosure use;

Small sample size & more research recommended but interesting findings with applications to fish management & welfare.

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A Global Survey of Current Zoo Housing and Husbandry Practices for Fossa: A Preliminary Review 
(Harley, O'Hara & Rose, 2021)

July 2021

New study in JZBG surveyed the global zoo husbandry practices for the fossa:

All animals receive enrichment & most have at least an area away from visitors but majority express unnatural behaviours;

Unnatural behaviour may be reduced with dense cover, restricted public viewing areas, variable feeding schedule & reduced view of other species;

41% of surveyed "breeding individuals" have bred at the zoo;

Important applications to fossa husbandry & welfare.

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Visitor attachment to dolphins during an interaction programme, are there implications to dolphin behavior? (Welsh & Ward, 2021)

July 2021

A study in Zoo Biology investigated the impacts of human-dolphin interactions on both bottlenose dolphins and the visitors:

Human participants reported a sense of attachment to the animals after interaction -applications to conservation education?

Dolphins showed no significant changes in behaviour - neutral effect on their welfare?

Small sample size - further research required.

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DNA Damage as a Potential Non-Invasive Indicator of Welfare: A Preliminary Study in Zoo-Housed Grizzly Bears (Ursus arctos horribilis(Fuller, Hamilton & Allard, 2021)

June 2021

A new paper in JZBG investigated the applications of DNA damage as an indicator of animal welfare in three zoo-housed grizzly bears:

DNA damage significantly increased with adrenal activity (faecal glucocorticoid metabolites);

Relationship between DNA damage and social affiliative behaviours varied between individuals;

Potential for DNA damage to be used in animal welfare assessments, but further research & validation required.

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Photo credit: Detroit Zoo

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Estimates of locomotion in Asian elephants Elephas maximus using video monitoring at Dublin Zoo, Ireland (Brady et al., 2021)

April 2021

A study in JZAR looked into behaviour & locomotion of the Asian elephants at Dublin Zoo, using CCTV footage:

Mean daily distance travelled (9.35 km/day) comparable to wild individuals (5-10 km/day);

50% of time spent foraging & 18% spent moving;

Locomotion & behaviour in these elephants closer to wild than previous zoo studies;

CCTV footage offers opportunities for behavioural research.

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Photo credit: Dublin Zoo

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Activity, Social Relationships, and Maternal Care in a Bottlenose Dolphin Group under Professional Cares (Lauderdale & Miller, 2021)

May 2021

A study in in JZBG looked into social relationships and maternal care in zoo-housed bottlenose dolphins:

Affiliative behaviours were dominant;

Strong mother-calf associations through 2nd and 3rd years of life;

Some individuals kept preferred associations, while others changed;

No large reductions in associations observed - strong relationships between individuals.

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A System for Monitoring Acoustics to Supplement an Animal Welfare Plan for Bottlenose Dolphins (Jones et al., 2021)

April 2021

A study in JZBG described the application of an acoustic monitoring system for captive bottlenose dolphins:

Software automatically compares acoustic behaviour of dolphins with past records;

Changes in acoustic behaviour can be detected - health & welfare problems?

Can help identifying problematic acoustic sources for the dolphins;

Applications to welfare monitoring of dolphins in zoos & aquariums.

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Influences of Rearing Environment on Behaviour and Welfare of Captive Chilean Flamingos: A Case Study on Foster-Reared and Parent-Reared Birds(Kidd & Rose, 2021)

April 2021

How does rearing environment affect the behaviour of captive Chilean flamingos? A new study in JZBG compared foster-reared and parent-reared chicks:

Foster-reared chicks: less time feeding, fewer preferred associations and more likely to occupy nesting area;

Social bonds were equally strong and durable in both foster-reared & parent-reared chicks;

Cross-fostering has limited impacts on behavioural and social development.

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Evaluating the Effect of Visitor Presence on Nile Crocodile (Crocodylus niloticus) Behavior (Riley et al., 2021)

March 2021

A study in JZBG looked into visitor effects on zoo-housed Nile crocodiles:

Behaviour was significantly affected by time of day, temperature & month;

Visitor effects on behaviour were found to be small/neutral.

Environmental variables should be considered when assessing behaviour and welfare in zoo-housed reptiles.

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Photo credit: David R. Tribble (Nile crocodiles at Disney's Animal Kingdom).

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Personality of killer whales (Orcinus orca) is related to welfare and subjective well-being (Úbeda et al., 2021)

March 2021

A paper in Applied Animal Behaviour Science investigated whether questionnaires can be used to reliably assess and monitor the welfare of captive killer whales:

Results validated questionnaires as an accurate welfare assessment tool for captive orcas;

High correlation between personality, welfare & subjective well-being;

Findings were similar to previous research on primates.

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Photo credit: Loro Parque

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Assessing the behaviour, welfare and husbandry of mouse deer (Tragulus spp.) in European zoos (Lemos de Figueiredo et al., 2021)

March 2021

A study in Applied Animal Behaviour Science, authored by our very own Ricardo, investigated what husbandry & management practices were affecting mouse deer breeding & behaviour in European zoos:

Vegetation cover positively affected breeding, activity & natural behaviours;

Water ponds and enrichment also had positive effects on activity & natural behaviours;

Close proximity between males and females negatively impacted breeding;

Diet and temperature they are housed in is likely suboptimal and requires further research;

Mouse deer benefit from complex enclosures, with ample vegetation, natural features and opportunities to avoid conspecifics.

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Photo credit: Copenhagen Zoo

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Effects of Nearby Construction Work on the Behavior of Asiatic Lions (Panthera leo persica) (Williams et al., 2021).

March 2021

Research in  JZBG looked into the effects of construction work on the behaviour of zoo-housed lions:

During construction: increased pacing (male), decreased resting (all three lions);

Sound & ground vibrations more likely to have been the stressors;

No long-term effects - behavioural changes not detected one year later;

Mitigation measures suggested.

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Photo credit: Chester Zoo

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Activity budget of zoo-housed Dolichotis patagonum mates (Baechli et al., 2021)

January 2021

A new study in JZAR looked into the activity budgets of zoo-housed Patagonian maras:

"Resting", "Feeding" & "Alert" were the most frequent behaviours;

High behavioural synchrony between mates;

Available data from wild individuals suggested a positive behavioural activity in these captive individuals.

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Photo credit: Hat.net

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Zoo soundscape: Daily variation of low‐to‐high‐frequency sounds (Pelletier et al., 2020)

July 2020

Noise at the zoo is a concern for animal welfare. Study in Zoo Biology assessed the soundscape (infrasounds and ultrasounds) of Zoo de Granby:

Sound levels increased during the day & with visitors present;

Sound levels generally not problematic for animal welfare;

Some locations showed high sound levels (e.g. indoor areas & touristic features);

Mitigation actions proposed.

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Contextual impacts on individual and synchronous breathing rate variations in three captive odontocete groups (Serres et al., 2020)

November 2020

A study investigated individual & synchronous breathing rate variations in three captive cetacean species:

Highest rates during energetic & social behaviours;

Higher rates during unusual events;

Enrichment: lower individual but higher synchronous rates;

Higher rates for ONE of the species in presence of public & during social separation;

Breathing rates are a useful parameter BUT should be interpreted carefully & integrated with other indicators.

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Photo credit: Baiji Dolphinarium

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Longitudinal Improvements in Zoo-Housed Elephant Welfare: A Case Study at ZSL Whipsnade Zoo (Finch et al., 2020)

November 2020

New study assessed the welfare improvements of the Asian elephants at ZSL Whipsnade Zoo, using data from their species-specific behavioural monitoring programme. Some of their findings include:
Species-appropriate levels of feeding;
Low levels of stereotypic behaviours;
Rare agonistic behaviour between group members;
Positive social associations & interactions between group members.

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Specialised for the Swamp, Catered for in Captivity? A Cross-Institutional Evaluation of Captive Husbandry for Two Species of Lechwe (Rose & Rowden, 2020).

October 2020

There is a new published paper on zoo husbandry practices in lechwe - a wetlands social antelope that is understudied in captivity:
Similar male:female ratios in captive and wild herds;
Enclosures usually included wetland areas, which were rarely managed;
Vegetation cover was limited;
Similar diets between zoos, but different from guidelines;
Abnormal behaviours reported but causes not identified.

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Photo credit: San Diego Zoo

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The 2020 Five Domains Model: Including Human–Animal Interactions in Assessments of Animal Welfare (Mellor et al., 2020).

October 2020

The Five Domains Model of animal welfare assessment has just been updated in a new paper:
Five Domains: (1) Nutrition, (2) Physical Environment, (3) Health, (4) Behavioural Interactions, (5) Mental State;
Update adds human-animal interactions to the model;
Applicable to all animal caretakers, including zoo keepers, researchers & veterinary staff!

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The Use of a Species-Specific Health and Welfare Assessment Tool for the Giant Pacific Octopus, Enteroctopus dofleini (Holst & Miller-Morgan, 2020)

September 2020

A new study has proposed a health & welfare assessment tool for the Giant Pacific octopus:

 Categories assessed: external appearance, behaviour & signs of stress and disease;

 Severity score system;

 Upward trend in score identified within 3-4 weeks of death - predictor?

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Photo credit: Aquarium of the Bay

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Seasonal and Daily Activity of Two Zoo-Housed Grizzly Bears (Ursus arctos horribilis)

August 2020

New study investigated activity patterns in two zoo-housed grizzly bears:
Most inactivity recorded in winter;
Stereotypies and general activity emerged in spring and summer;
Stereotypies more frequent in the morning.