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N. A. river otters: San Francisco Zoo, California

“What is an enriched environment? It is one that allows animals to perform

natural behaviors, gives animals control over their lives, eliminates frustration,
makes captive environments more interesting, gives animals more choice, and
allows animals to be more active. Enrichment of the enclosure involves the
physical environment including shape, size and complexity. Complexity consists
of an animal environment such as visual barriers, climbing or traveling structures,
substrates, rest/sleep areas and temporal complexity. Manipulable objects such
as toys and vegetation, the opportunity to use five senses, and the social
environment are all beneficial to the animal. The types of food offered, the
frequency and presentation play a large role in enriching the lives of our captive
charges.
(Grams, K. 2000. Exhibitry and Enrichment of North American River Otters (Lontra
canadensis) at The Arizona-Sonora Desert Museum. Animal Keepers’ Forum, Vol. 27,
No. 4. Quotation is referencing a presentation given by D. Shepherdson & J. Mellen at
the First Environmental Enrichment Conference in Portland, Oregon, 1992.)

When developing your otter enrichment program do not forget the

importance of your exhibit design. A complex, well thought out exhibit will
provide a multitude of enrichment options. Exhibit furniture can be moved (both
onshore and “offshore”) and should be changed periodically to introduce novelty
to the animals’ environment. It is preferable to offer a variety of substrates. This
affords the animals a choice of where to do their grooming and allows for a range
of exploratory behaviors which can be encouraged by planting toys, food items,
etc. throughout the exhibit. Pools, streams, waterfalls, etc. need to be varied in
depth; if possible, water bodies in the same exhibit should also offer different
features such as degree of turbulence, shore composition, and submerged
fixtures like logs, rocks, etc. Stones, rocks, pebbles, and non-abrasive sand
placed along the shoreline, or as part of shallow water bodies, offer a rich
medium for manipulation by the otters and hiding of treats and toys. Temporal
enrichment can be a valuable option for those exhibits designed with adequate
off-exhibit holding facilities. Animals can be rotated on and off exhibit providing
them with the opportunity to explore different spaces, get away from the public or

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other animals for awhile, pursue a more natural behavior cycle like following the
scent of an estrous female, and finally, periodic rotation of animals stimulates
activity in the exhibit and creates an opportunity for keepers to introduce other
enrichment items to the exhibit. Indoor exhibits should offer temperature
gradients to allow animals the choice of where they want to be and outdoor
exhibits should provide varying degrees of shade. Sleeping/hiding place choices
should be available in any exhibit type.
And finally, when looking for new enrichment items keep these criteria in
mind: “First, the object must be large enough so that it cannot be ingested.
Second, it must be strong enough to stand up to their teeth. Third, it cannot have
any sharp edges that could cut the otters. Fourth, it cannot have any small parts
that could break off…” (Gabbert 1999)

Development of enrichment ideas should be goal-oriented, proactive,

based upon the animal’s natural history, individual history, and exhibit
constraints, and should be integrated into all aspects of their captive
management. Providing the appropriate enclosure designs (e.g., land/water
ratios, pool/land designs), substrates, and furnishings for each otter species are
essential components of any enrichment program. Enrichment should encourage
otters to behave as they would in the wild, as closely as possible. Successful
enrichment techniques include, variation of exhibit schedule or exhibit mates
(where appropriate only), re-arranging of exhibit furniture/features, complete
change of furniture (some of the old should always be retained to maintain the
animal’s scent and an element of the familiar), scents, sounds, toys (natural and
artificial), herbs, spices, different substrates for digging/rolling, food items, and
novel presentation of food items. It is important that enrichment items are not
merely thrown in an exhibit and allowed to stay for extended periods – an
enrichment program is only successful and useful if actively managed and
constantly reviewed to ensure it encourages natural behaviors. The AAZK
Enrichment committee provides the follow general guidelines about enrichment:

“The goal of enrichment should be to maximize the benefit while

minimizing unacceptable risks. All enrichment should be evaluated on three
levels: 1) whether the enrichment item itself poses an unacceptable risk to the
animals; 2) what benefit the animals will derive from the enrichment; and 3)
whether the manner of enrichment delivery is apt to lead to problems.
A written plan of action that eliminates the most dangerous risk factors
while maintaining the benefits of a challenging and complex environment can
help animal managers develop a safe and successful enrichment program.
Keepers should evaluate new and creative enrichment ideas with their managers
and staff from other departments (curatorial, janitorial, maintenance, veterinary,
nutritional, etc.) to decrease the frequency of abnormal and stereotypic behaviors
or low activity levels, and to fine-tune enrichment ideas. For enrichment to be
safely provided, it is strongly recommended that each institution establish
enrichment procedures, protocols, and a chain of command that keepers can
follow.” (AAZK Enrichment Committee)

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The AAZK Enrichment Committee also provides an excellent cautionary

list for the various types of enrichment provided (accessed through
www.aazk.org). This list includes key questions that should be answered for all
enrichment items or programs to assess potential hazards. For example:
1. Can the animals get caught in it or become trapped by it?
2. Can it be used as a weapon?
3. Can an animal be cut or otherwise injured by it?
4. Can it fall on an animal?
5. Can the animal ingest the object or piece of it? Is any part of it toxic,
including paint or epoxy?
6. Can it be choked on or cause asphyxiation or strangulation?
7. Can it become lodged in the digestive system and cause gut
impaction or linear obstruction?
8. In a multi-species exhibit or other social grouping, could a larger or
smaller animal become stuck or injured by the object or get hung up
on it?
9. Can it destroy an exhibit?
10. If fecal material is used for enrichment, has it been determined to be
free from harmful parasites?
11. Is food enrichment included as part of the animals' regular diet in a
manner that will reduce the risk of obesity?
12. When introducing animals to conspecifics or in a multi-species exhibit,
are there sufficient areas for them to escape undesirable interactions?
13. Can the manner of enrichment presentation (i.e., one item or items
placed in a small area) promote aggression or harmful competition?
14. Has browse been determined to be non-toxic?
15. Do the animals show signs of allergies to new items (food, browse,
substrates, etc.)?
16. Does the enrichment cause abnormally high stress levels?
17. Does the enrichment cause stimulation at a high level for extended
periods of time that do not allow the animal natural down time in the
species' normal repertoire (e.g., constant activity for public enjoyment
when the animal would normally be inactive in its native habitat)?

Factors that should be considered when determining how often behavioral

or environmental enrichment is offered include the species and individual(s)
involved as well as the physical characteristics of the exhibit. Large, complex
exhibits with appropriate enclosure designs, substrates, and furnishings may
offer ample opportunities for animals to exercise natural behaviors with
infrequent enrichment (once daily). Other exhibits or individuals may require
more frequent enrichment (multiple times per day). Husbandry staff should
monitor all individuals in an exhibit and structure an enrichment schedule for the
needs of those animals, providing them opportunities several times a day to
interact positively with their environment. Enrichment should never be offered on
a regular schedule, instead times, items, and delivery methods should be rotated
so there is always an element of novelty associated with each item or activity. It
is important to note that the provision of well-designed, complex environments is
the foundation of a successful enrichment program. This is particularly true for

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some of the more sensitive otter species such as L. brasiliensis, but applies to all
of the otter species due to their inquisitive nature and high-activity level.

References:

Gabbert, A. 1999. An “Otterly” Enriching Environment”. Shape of Enrichment.

Vol. 8, No. 2, May 1999.

Appendices:

Appendix A: How can a zoo enclosure be enriched – broad concepts

Appendix B: Enrichment items – Tables
Appendix C: AAZK Enrichment Committee, Enrichment Caution List

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Appendix A

“How Can a Zoo Enclosure be Enriched?”*

(Excerpt from: Reed-Smith 2001: N. A. River Otter Husbandry Notebook)

Physical Environment Social Environment

Size & Shape Conspecific
Complexity Group size and composition (wild as a model)
Visual Barriers Contraspecific
Climbing/Travel Structures Mixed Species
Substrates
Rest/Sleep Areas Occupational Enrichment
Temporal Complexity Learning
Manipulable Objects Training
Toys Puzzles
Vegetation

Food
Type Presentation
Novelty Hidden
Variety Whole Food
Treats Dispersed
Delivery Live Food
Frequency Processing Time, etc.

The Senses
Auditory Taste
e.g. Taped Vocalizations Variety
Olfactory Novelty
Scents Seasonal Change
Faeces (conspecifics, other species)
Spices
Tactile
Texture
Manipulable Objects
Novelty

* Take from: Compendium of Enrichment Ideas, Proceedings of 1st Conference on

Environmental Enrichment 1993, Oregon Zoo, 4001 S. W. Canyon Rd., Portland, Oregon 97221.

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Appendix B: ENRICHMENT ITEMS – Table (Reed-Smith 2001)

Natural Exhibit Non-edible Live Food Edibles
Furniture manmade
Soil, sand, mulch, Climbing areas Boomer balls – all Fish (smelt, shiners, Ice blocks w/ fish,
etc. (technically available sizes & various gold fish, trout, fish-sicles, fish
in all exhibits, i.e. products like the salmon, mackeral, cubes, etc.
cliffs, ledges, etc.) “spoolie” & “ice tilapia)*others listed krill cubes, clam
cube” below cubes, etc.
Grass, sedges, etc. Logs (on land, Ice blocks, cubes, Crayfish Frozen or thawed
submerged, floating; pops, etc. sand eels
hollow &/or solid)
Trees Rocks (not artificial) Natural snow & ice Crickets Fish pieces
Bushes Waterfall Dog chews, rawhide Fly-in birds Scattered carrot
treats pieces
Vines, “vine hoops” Stream PVC cricket feeder Giant mealworms Chicken necks
Aquatic plants Sticks Buckets Earthworms Mice
Hay, straw, grass, Browse (leafy Blankets, burlap, Freshwater clams Whole fish – frozen
leaves, wood wool as branches on land hammock, non- or thawed
bedding &/or floating fraying rags
Grass piles Slides Barrels of water Mussels Whole
Frisbees apples/oranges
Leaf piles Tunnels Tubs of water Krill Fruit & berries (incl.
grapes, blueberries,
Carpet over board
strawberries)
Rocks, all sizes for Stream bed Rubber-coated Eels – naturally Small
play & manipulation Running water heating pad* found pumpkins/squash
Knot holes Holts Astro turf Shrimp Omnivore biscuits
Bark sheets Jacuzzi-like jets in Floating plastic toys Aquatic insects – Monkey chow
Pine cones pool Phone Books naturally found Pigs ears
Mud Islands in pools Swim through plastic Mice – naturally Frozen blood blocks,
Sod ring found cubes, etc.
Bank over-hangs Bridges made from Kids puzzle balls, Frogs – naturally Hard-boiled eggs
logs, etc. Frisbees, billiard found
balls, hard balls
Floating wood Stumps Diff. size pieces of Grubs Day-old chicks
blocks PVC pipe & fittings Crabs
Pine needles Natural fiber mat Kong chews Chub Melons
Other animal urines Movable sand box Metal bowls & pans Minnows Coconuts
Powdered scents & Logs brought from Plastic containers & Bluegill Frozen feline balls
herbs other exhibits bottles*
Fresh herbs Log ladder Bread tray Clams Milk bones
Extracts – i.e. Non-sprayed Xmas Kids plastic slide, Mud minnows Screw pine nuts,
vanilla, etc. trees house unsalted peanuts
Grapevine balls Moving soil pots Stock tank Krill patties
Shells Hanging logs w/ Hanging tub* Hampster ball w/
Turkey feathers holes for food Warm water hose treat
Corn Stalks Snow Piles Vari-kennel Gelatin Jigglers
Blowing bubbles into Piles of ice cubes Tubs w/ different Corn on the cob
exhibit substrates Chicken necks
Kudzu vines PVC tube hung for Yogurt w/ fish
Cow Hooves climbing in. Unsalted ham
* Any item used from this list should be cleared with zoo management and carefully monitored. The items with asterisks should be
closely watched, I do not know if any problems ever arose with these things. Many people use paper products however caution
should be exercised, there have been problems when the paper becomes wet and “glues” itself to an animals mouth. The same
holds true for cardboard.

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The table below lists items used at various North American facilities for behavioral
and environmental enrichment of otters.
Non-edible
Natural Exhibit Furniture Live Food Edibles
manmade
- Soil, sand, mulch - Climbing areas - Boomer balls and - Fish (smelt, - Ice blocks w/fish,
- Grass, wheat (available in all other products like shiners, goldfish, fish-sicles, fish
grass, sedges, etc. exhibits, i.e., the "spoolie", trout, mackerel, cubes, etc.
- Trees cliffs, ledges) “bobbin” & "ice tilapia salmon)* - krill cubes, clam
- Vines "vine - Logs (on land, cube". - Crayfish cubes, etc.
hoops" submerged, - Ice blocks, cubes, - Crickets - Frozen or thawed
- Aquatic plants floating; hollow pops. - Giant mealworms sand eels
- Hay, straw, grass, and/or solid) - Snow & ice - Earthworms - Fish pieces
leaves, wood - Rocks (not - PVC cricket - Freshwater clams - Chicken necks
wools as bedding artificial) feeder - Mussels - Mice
- Grass piles - Stream - Buckets - Krill - Whole-fish -frozen
- Leaf piles - Sticks - Blankets, burlap, - Eels- naturally or thawed
- Rocks, all sizes for - Browse (leafy non-fraying rags, found - Whole
play and branches on land towels - Shrimp apples/oranges
manipulation and/or floating) - Barrels of water - Aquatic insects - - Fruit & berries
- Knot holes - Slides - Frisbees naturally found incl. grapes,
- Bark sheets - Tunnels - Tubs of water - Mice- naturally blueberries,
- Pine Cones - Stream bed - Carpet over board found strawberries
- Mud - Running water - Rubber-coated - Frogs – naturally - Small pumpkins
- Sod - Holts heating pad* found and squash
- Bank over-hangs - Jacuzzi-like jets in - Astro turf - Grubs - Omnivore biscuits
- Floating wood pool - Floating plastic - Chub - Monkey chow
- Blocks - Islands in pool toys - Minnows - Pigs ears
- Pine needles - Bridges made - Phone books - Bluegill - Frozen blood
- Other animal from logs, etc. - Swim through - Clams blocks, cubes, etc.
urines - Stumps plastic ring - Mud minnows - Hard-boiled eggs
- Powdered scents - Natural fiber mat - Kids puzzle balls, - Day-old chicks
and herbs - Movable sand box billiard balls, hard - Crabs
- Fresh herbs - Logs brought from balls - Melons
- Extracts, i.e., other exhibits - Pieces of PVC - Coconuts
vanilla, etc. - Log ladder pipe and fittings - Frozen feline balls
- Grapevine balls - Non-sprayed - Kong chews - Milk bones
- Shells evergreen trees - Metal bowls and - Screw pine nuts,
- Turkey feathers - Moving soil pots pans unsalted peanuts
- Corn stalks - Hanging logs with - Plastic tubs and - Krill patties
- Blowing bubbles holes for food bottles - Hamster ball w/
into exhibit - Snow piles - Bread tray treat
- Kudzu vines - Piles of ice cubes - Plastic slide, house - Gelatin Jigglers
- Cow hooves - Stock tank - Corn on the cob
- Hanging tub* - Yogurt with fish
- Warm water hose - Unsalted ham
- Vari-kennel tubs
with substrates
- PVC tube hung for
climbing in
* These items should be monitored for safety.

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Point Defiance Zoo and Aquarium, Oregon, USA – ASC otter

Non-food items - Traffic cones
- Boomer balls & Jolly balls - Hummus
- Bowling pins - Ice piles
- Brushes - Rose petals
- Bucket lids - Burlap sacs
- Beer kegs, feed barrels & trash cans - Straw piles
- Feed bags - Reindeer antlers
- Clover clumps - Varied of feeding devices & times
- Milk crates, Plastic wagons & Plastic logs - Nyla bones
- Water cooler bottles - Spices and extracts
- Grass flats/clumps - Mirror
- Hang paper maché figures
- Hollow coconut shells Food items
- Oscillating fan, wind chimes, & bubble machine - Honey smears
(outside of enclosure) - Blood popsicles
- Large logs, rearrange furniture, etc. - Cooked chicken
- Leaves, sand, and rock piles - Crickets
- PVC tubes - Horse meat
- Towels, clothes, blankets - Meal worms
- Cardboard boxes and tubes (caution needed when - Peanut butter
using paper products that can become wet) - Pinkies
- Laser pointer - Dry cat food
- Nature tapes - Milk bones
- Perfume/body sprays & Glad scented sprays - Tuna

Columbus Zoo and Aquarium, Ohio, USA – N. A. river otter/ASC otter

Non-food items - Pig ears and cow hooves
- Bobbin with smelt rubbed on it - Painting
- Whole coconuts to roll around - Mustard or tomato sauce
- Yellow pages - Large black kong toy
- Bengay™ ointment inside a boomer ball - Floating PVC tube to swim through
- Log switching between animal exhibits
- Regular Alka Seltzer® in PVC tube (very small holes Food items
in PVC) - Liver
- Corn stalks - Anchovy paste
- Blocks of recycled plastic with holes drilled in them - Hard boiled eggs, apples, pumpkins,
to dig food items out carrots, blueberries
- Crickets in PVC tube feeder - Gelatin jigglers
- PVC shaker toys - Live crawdads, live trout in pool,
- Milk crates, cardboard box, use with caution crickets
- Pinecone soaked in scents - Frozen smelt ice blocks
- Extracts – vanilla, almond, lemon & spices - Blood popsicles
- Elephant manure - Knuckles
- Deodorant spray - Beef hearts
- Reindeer antlers & pronghorn sheaths - Mice and rats
- Paper maché

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Appendix: C

AAZK Enrichment Committee, Enrichment Caution List

http://www.aazk.org/committees/enrichment/comm_enrichment_title.php

The AAZK Enrichment Committee offers several useful resources that can be
accessed through the web site.

Dietary Enrichment
- Food enrichment, if uncontrolled, can lead to obesity, tooth decay and deviation from the
normal diet can cause nutritional problems. Keepers can consult with the nutritionist or
commissary staff to determine the best method of introducing novel food items.
- New food items introduced without analysis may cause colic, rumenitis or metabolic acidosis
in ungulates.
- Food items can spoil and cause animal illness if left in the exhibit for extended periods of
time. Enrichment food items should be removed within a reasonable amount of time to
prevent spoilage.
- Animals can have adverse reactions to toxic plants and chemicals. Keepers should be able to
correctly discern between toxic and browse plants, ensure that browse is free of fertilizers and
herbicides and wash plants to remove free ranging bird and animal feces and debris.
- Foraging or social feedings may give rise to aggression and possible injuries within the
animal population.
- Competition for enrichment items may lead to social displacement of subordinate animals.
These concerns can be minimized by providing enough enrichment to occupy all of the
animals within the population.
- Carcass feedings for omnivores and carnivores may be hazardous if the source of the carcass
is not determined and appropriate precautions taken. Diseased animals, chemically
euthanized animals or those with an unknown cause of death are not appropriate for an
enrichment program. Freezing the carcasses of animals that are determined to be safe to feed
to exhibit animals can help minimize the risk of parasitism and disease. Providing enough
carcasses in group feedings can minimize competition and aggression within an exhibit.
- Carefully introducing a group of animals to the idea of social feedings can be done by
moving carcass pieces closer together at each feeding until the animals are sharing one
carcass. This can allow social carnivores to exhibit normal dominance posturing while
minimizing the possibility of aggression. During live feedings, prey animals may fight back.
Care should be taken to ensure such prey can only inflict superficial wounds on zoo animals.
- Cage furniture may interrupt flight paths or entangle horns and hooves if poorly placed.
Careful planning can prevent this.
- If unsecured, some items may fall on an animal or be used as a weapon and cause injuries.
- If position is not thoughtfully considered, limbs and apparatus may provide avenues for
escape or may block access into exhibit safety zones, leaving subordinate animals feeling
trapped and vulnerable.
- Animals that crib or chew wood should be provided with non-toxic limbs and untreated wood
furniture.
- Water features should be tailored to the inhabitants to prevent drowning and ensure that
animals such as box turtles can right themselves if they flip over on their backs.
- Animals can be injured in filtration systems if water intake areas are not protected.
- Substrates should provide adequate traction and not cause an intestinal impaction if ingested.
- Caution should be exercised when ropes, cables, or chains are used to hang or secure articles
to prevent animals from becoming entangled. Generally, the shortest length possible is

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recommended. Chain can be covered with a sheath such as PVC pipe; swivels can be used to
connect the chain to the enrichment item to minimize kinking.

Olfactory Enrichment
- Scents from different animals or species can lead to aggression if there is an assertion of
dominant animals or subordinate animals attempting to use enrichment to advance their status
in the heirarchy.
- Animal feces used for olfactory enrichment should be determined to be parasite free through
fecal testing and as with other animal by-products such as feathers, sheds, wool and hair,
come from only healthy animals. Many of these items can be autoclaved for sterilization.
- Perfumes can be overwhelming to some animals (and keepers) and are therefore best used in
open, ventilated areas.
- Some spices may be too strong or toxic to some animals.

Auditory Enrichment
- When provided with audio enrichment, animals may be less threatened by deflected sounds
rather than those directed at the animals.
- Some animals may have adverse reactions to recordings of predator calls and should be
closely observed when this type of enrichment is provided.
- Providing the animals with an option for escape or the means to mobilize for confrontation
when predator calls are played can lessen the stress of this type of enrichment and allow the
animals to investigate the sounds and their environment over a period of time.
Manipulable Enrichment
- Individual parts or enrichment devices may be swallowed resulting in choking or
asphyxiation.
- If ingested, indigestible enrichment items may cause a gut impaction or linear obstruction.
- Broken items may have sharp edges that can cut an animal. Only items that are appropriate
for the species should be provided. For example, some devices will hold up to the play of a
fox but not a wolf
- When building or designing enrichment items from wood, it may be wise to use dovetail cuts
and glue rather than screws and nails. Rounded corners and sanded edges can prevent the
animals from getting splinters.
- Many paints and other chemicals are toxic if eaten. When providing enrichment involving
paint or other chemicals, only non-toxic items should be used.
- If used, destructible items such as cardboard boxes and paper bags should be free of staples,
tape, wax, strings or plastic liners. In general the Otter SSP advises against using these items.

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