Environmental Enrichment

Scientific Papers

White Bear

© Rory Harper

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An investigation of browsing enrichment, especially non-leaf foraging, on giraffes (Giraffa camelopardalis reticulata) at Kyoto City Zoo in Japan (Okabe et al., 2022)

August 2022

A paper in Zoo Biology looked into browsing enrichment in zoo-housed giraffes:
No differences in behaviour between green-leaf & deciduous phases;
Vegetation foraging decreased in deciduous phase, but dry hay foraging increased;
Twig & bark foraging increased in the deciduous phase for some individuals;
Giraffes foraged on twigs & bark of some tree species to compensate for the lack of leaves.

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Foraging enrichment affects behaviour and enclosure utilisation in captive male gelada Theropithecus gelada
(Hurley & Cotton, 2022)

July 2022

A study in JZAR investigated the effects of a foraging enrichment device on the behaviour and enclosure use of a group of zoo-housed male geladas:
  Increase in time consuming food & foraging wild foliage;
  Foraging time budgets more similar to wild during enrichment;
  Greater enclosure use during enrichment.

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Material and food exploration by zoo-housed animals can inform cognition and enrichment apparatus design
(Clark, Chivers & Pearson, 2022)

May 2022

A paper in Zoo Biology investigated how a group of zoo-housed ring-tailed lemurs explored novel materials & whole foods, to inform future cognitive apparatus:
 Preference to explore wooden surfaces;
 Metal produced too much heat & glare,  and untreated wood was easily destroyed by biting & chewing (materials to avoid);
 Olfactory exploration was more common than touch, but they used one or two hands for manipulation;
 Applications to cognitive research & enrichment.  

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Environmental enrichment for collared peccaries Dicotyles tajacu, Tayassuidae in managed care: Different items provoke different behavioural responses (de Faria et al., 2022)

April 2022

A paper published in Journal of Zoo & Aquarium Research explored the effects of different enrichment items (basins with food, cardboard boxes with paper & food, scent trails, piles of straw with food) on the behaviour of captive collared peccaries:
 Exploration & behavioural diversity increased;
 Inactivity decreased;
 Straw pile and carboard boxes were particularly effective;
 Enrichment associated with food rewards had the most impact on behaviour;
 Applications to husbandry & welfare of this species in captivity.

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Training as enrichment: A critical review (Fernandez, 2022)

February 2022

A paper in Animal Welfare reviewed the enrichment potential of training in captive animals::
 Three ways training may be enriching:
1. Facilitating the use of enrichment;
2. Modifying interactions;
  3. Expanding behavioural repertoires.
 Previous studies suggest the enrichment value of training, but further research is recommended.

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Testing use of the first multi-partner cognitive enrichment devices by a group of male bottlenose dolphins (Matrai et al., 2022)

February 2022

A study in Animal Cognition tested a cognitive enrichment device that required cooperative manipulation on a group of five captive bottlenose dolphins:

A three-way and a four-way devices were created using PVC tubes equiped with rope handles and filled with fish and ice;

To open the devices, the dolphins had to pull the ropes simultaneously;

Dolphins received no previous training but were successful at opening both devices in 10 out of the 12 trials;

Interaction with the device observed during entire testing period , most of it was cooperative play.

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Rehabilitation of Marine Turtles & Welfare Improvement by Application of Environmental Enrichment Strategies (Escobedo-Bonilla, Quiros-Rojas & Rudin-Salazar, 2022)

January 2022

A review in Animals discussed the importance of enrichment techniques in improving welfare & rehabilitation of marine turtles in short- and long-term captivity:

Five case studies reviewed;

Enrichment can improve welfare of marine turtles while in rehabilitation and promote natural behaviours;

Enrichment also improves chances of reintroduction success in physically damaged turtles or those in long-term captivity.

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Environmental Enrichment Factors Associated with the Activity Level of Bottlenose Dolphins under Professional Care (Lauderdale et al., 2022)

January 2022

A new study in JZBG the relationship between the activity of captive dolphins and the buoyancy & provision schedule of enrichment:

Positive relationship between activity & duration of non-stationary enrichment;

Positive relationship between activity and larger number of enrichment types provided on rotation;

Negative relationship between activity and number of times sinking enrichment was provided;

Applications to enrichment programmes for captive dolphins.

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Evaluating Environmental Enrichment Methods in Three Zoo-Housed Varanidae Lizard Species (Waterman et al., 2021)

December 2021

A study in JZBG evaluated enrichment methods in three zoo-housed Varanidae species:

Exploratory behaviour increased with scent piles, scent trails & hanging feeders;

Engagement with enrichment decreased over time;

No differences in engagement between scent and food-based enrichment - both effective;

Applications to husbandry of this poorly studied taxon.

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Interest in coloured objects and behavioural budgets of individual captive freshwater turtles (Thomson et al., 2021)

November 2021

A paper in JZAR investigated a potential relationship between escape behaviour in captive freshwater turtles & their interest in coloured objects:

High & moderate escape behaviour: more interest in coloured objects & reduced escapes in their presence;

Low escape behaviour: less interest in the objects & increased escapes in their presence;

interest in yellow objects with more contacts before feeding & at start of observation period.

Applications to turtle enrichment programmes.

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The effect of different types of environmental enrichment on Humboldt penguin Spheniscus humboldti behaviour (Razal & Miller, 2021)

November 2021

A study in JZAR investigated the effect of enrichment on the behaviour of zoo-housed Humboldt penguins:

Enrichment tested: (𝟏) artificial sticks, (𝟐) live minnows, (𝟑) floating island, (𝟒) feeding penguins in water;

Artificial sticks significantly increased activity levels;

No significant differences detected for other enrichment types.

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Investigating the Effect of Enrichment on the Behavior of Zoo-Housed Southern Ground Hornbills
(Brereton, Mayhill & Shora, 2021)

November 2021

New paper in JZBG looked into the effects of enrichment on the behaviour of zoo-housed southern ground hornbills:

Three types of enrichment: pile of twigs, small animal carcasses & plastic mirrors;

Carcasses & mirrors caused the greatest behavioural changes;

Carcasses: long periods of food manipulation;

Mirrors: stalking around & pecking, similar to "window smashing" wild-type behaviour;

Both food-based and non-food enrichment can be beneficial to zoo-housed animals;

The natural history of a species can inspire effective enrichment strategies.

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Should zoo foods be chopped: macaws for consideration (James et al., 2021)

November 2021

New study in JZAR looked into the effect of food presentation (whole and chopped fruit) on the behaviour of two pairs of zoo-housed blue-and-gold macaws:

Keepers spent significantly more time preparing diets with chopped fruit;

Activity budgets mostly the same in both food presentation regimes BUT...

Podomanipulation (i.e. foot use) and allofeeding significantly higher when whole fruit was presented;

Resting/inactivity significantly lower with whole fruit presentation;

Providing macaws with whole foods may be time-effective for animal care staff while encouraging wild-type feeding behaviours & reducing inactivity in the parrots.


Photo: Beale Wildlife Park

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Knowledge-based enrichment: Development of a novel enrichment device for captive chimpanzees 
(Brooks, Yoshimura & Taki, 2021)

May 2021

A study in Zoo Biology tested a knowledge-based enrichment device on two groups of captive chimpanzees, where they had to retrieve small tubes containing hidden treats from a large tube:
Group with NO experience with the device: LOWER interaction than "knowledgeable" group UNTIL an individual retrieved first tube;
Rapid knowledge transmission between group members seemed to have occurred;
Individuals spent >20 minutes on average interacting with device (one-hour observation periods);
Knowledge can motivate enrichment use even when food rewards are not visible.

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Enrichment devices for green turtles (Chelonia mydas) reared in captivity programs (Kanghae et al., 2021)

May 2021

A new study in Zoo Biology tested the effect of several enrichment devices on the behaviour, health and welfare of captive young green turtles, raised in a head-starting programme:

Enrichment caused a decrease in biting wounds;

More interactions with ring-shaped enrichment than hollow-square, sphere and cylinder shapes;

Growth & feed utilisation not affected by enrichment;

Ring-shaped enrichment was the most effective.

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An evaluation of interactive projections as digital enrichment for orangutans (Carter et al., 2021)

January 2021

A study in Zoo Biology investigated the use of interactive projections as digital enrichment for zoo-housed orangutans:

Varied interactions with the enrichment were observed, especially among the younger individuals;

Digital enrichment did not have any significant effects on the orangutans' time budget;

Interactive projections do not require food rewards as motivation.

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Effects of Enclosure and Environmental Enrichment on the Behaviour of Ring-Tailed Lemurs (Lemur catta)(Laméris et al., 2021)

April 2021

A study in JZBG looked into the effects of type of enclosure and enrichment on the behaviour of zoo-housed lemurs:

Type of enclosure had stronger effects on behaviour than enrichment;

The effect of enrichment on behaviour differed between indoor and outdoor enclosures;

Enrichment programmes should be evaluated and not generalised across enclosures.

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The Effects of Live Feeding on Swimming Activity and Exhibit Use in Zoo Humboldt Penguins (Spheniscus humboldti) (Fernandez et al., 2021)

March 2021

New paper in JZBG looked into the effects of live feeding (trout) on the swimming activity and enclosure use of zoo-housed Humboldt penguins:
>30% total swimming increase in live feed days;
Increased (overall) enclosure use in live feed days;
Live feeding may be an effective enrichment strategy in this species.


Photo credit: Woodland Park Zoo

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Exploring How White-Faced Sakis Control Digital Visual Enrichment Systems (Hirskyj-Douglas & Kankaanpää, 2021)

February 2021

Research published in Animals investigated the use of an interactive video device as enrichment for saki monkeys at Korkeasaaren eläintarha:

Device gave sakis the choice to trigger different videos;
Underwater & worm videos triggered more than others (animals, abstract art, forest);
Scratching, which is potentially stress-related, decreased;
Device use eventually decreased - habituation?
Device potentially enriching, but challenges of quantifying interactions discussed.

Object Enrichment_Freshwater Turtles_Zoo

Can colored object enrichment reduce the escape behavior of captive freshwater turtles? (Bannister et al., 2021)

February 2021

A new study in Zoo Biology looked into the effects of enrichment (coloured objects, with & without fish scent) on the behaviour of aquarium-housed freshwater turtles:

Presence of coloured objects reduced escape behaviour;

Fish-scented objects attracted more interest;

Large individual differences in the behavioural response to enrichment;

Fish-scented, coloured objects have the potential to be beneficial for captive turtles, but individual monitoring is recommended.

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Assessing preferences of two zoo‐housed Aldabran giant tortoises (Aldabrachelys gigantea) for three stimuli using a novel preference test (Learmonth et al., 2020)

December 2020

A case study investigated the preferences of two Aldabran giant tortoises for three different stimuli/enrichment (human interaction, food and a red boomer ball):

One tortoise preferred food + ball while avoiding human interactions altogether;

The other tortoise preferred food + human interactions;

Stimuli/enrichment preferences show individual variation and depend on several factors.


Photo credit: Zoos Victoria

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Using longitudinal data to evaluate the behavioural impact of a switch to carcass feeding on an Asiatic lion (Panthera leo persica) (Finch et al., 2020)

October 2020

What is the long-term behavioural impact of carcass feeding on zoo-housed Asiatic lions? A lioness at Chester Zoo showed the following behavioural changes 12 months after the diet change:
Reduction in pacing;
Increase in resting behaviour;
Increase in feeding-related behaviours, shortly after & 12 months after the diet change.


Photo credit: Chester Zoo


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A persistent abnormal repetitive behaviour in a false water cobra (Hydrodynastes gigas) (Michaels et al., 2020)

November 2020

Fresh new paper looked into stereotypic behaviour in captive false water cobras:
Observed fixed pattern of movement against viewing window identified as potential stereotypy;
Snake spent some time in this repetitive behaviour, which was also reported by another zoo;
The enrichment used did not reduce the behaviour's frequency or changed the snakes' use of the enclosure.


Photo credit: Smithsonian's National Zoo


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Development of an environmental enrichment programme: case study of white Bengal tiger (Panthera tigris bengalensis) and jaguar (Panthera onca) at Moscow Zoo (Podturkin & Papaeva, 2020)

April 2020

A study investigated the effect of daily and every other day enrichment provision on the behaviour of a zoo-housed tiger and jaguar, using a time efficient, keeper-friendly, methodology:

Increase in enrichment-directed behaviours in both animals;

No significant effects on general activity - small sample size?

Methodology allowed keepers to implement & evaluate enrichment programme.