Carnivores: Hide food around enclosure

Supporting evidence from individual studies

1. A small before-and-after study in 1988 of a black bear Ursus americanus in a zoo in the USA found that when food was hidden around the enclosure (including inside objects) walking and stereotypical pacing behaviours decreased and exploring/foraging behaviours increased compared to when food was not hidden. Stereotypical pacing was lower when food was hidden around the enclosure (median 20 minutes/day) compared to being placed on the floor of the indoor area (median 125 minutes/day) as was walking whereas exploring/foraging was higher (mean values not reported). One black bear was fed once or twice daily before the study and during baseline data collection (8 days). During the first condition (6 days), the bear was still given the morning feed as well as a feeder tree containing snacks. The feeder tree released snacks at scheduled times of day, releasing food at six different locations. The second condition (8 days) included hiding all food apart from the meat around the enclosure, under rocks, in logs and in Boomer balls. Video recordings were taken for 12 hours starting 06:00 each and continuous focal sampling method was used.

   Study and other actions tested

   Referenced paper

   Carlstead K., Seidensticker J. & Baldwin R. (1991) Environmental enrichment for zoo bears. Zoo Biology, 10, 3-16.

2. A small replicated, before-and-after study in 1991 of leopard cats Felis bengalensis in off-exhibit enclosures in the USA found that multiple feeds hidden around the enclosure, increased time spent locomoting/exploring, increased behavioural diversity and decreased stereotypic pacing. Time spent locomoting (15.5 %/h) and behavioural diversity (0.547 Shannon index) increased and stereotypic pacing decreased (9.5%/h) compared to non-hidden food (locomoting: 6%/h; behavioural diversity: 0.458 Shannon index; pacing: 18.5%/h). Four cats were singularly housed and baseline data was collected for eight days before the treatment, when fed their regular diet of 0.25 kg of a commercial meat diet, an egg and one or two dead mice once daily. The hidden food treatment (5 days) included four feeds of either a mouse, chick and egg, or 0.125 kg of feline diet hidden in one of two piles of branches at irregular times of day. Continuous focal sampling from 24-hour video recordings was used to record behaviour and location.

   Study and other actions tested

   Referenced paper

   Shepherdson D.J., Carlstead K., Mellen J.D. & Seidensticker J. (1993) The influence of food presentation on the behavior of small cats in confined environments. Zoo Biology, 12, 203-216.

3. A small before-and-after study in 1995 of Canadian lynx Lynx canadensis in the USA found that hiding food around the enclosure reduced the time spent sleeping compared to when food was not hidden. The male lynx and first female lynx showed a reduction in time spent sleeping (1.1%) when food was hidden around the enclosure compared to when food was not hidden (30%). Before the study, the lynxes were fed each morning (processed feline meat, supplemented with dead day-old chicks, trout and mice). During the treatment phase, processed meat was fed each morning and dead prey items were hidden within the enclosure. Food was hidden daily for 17 days and hidden for two to three days a week for 10 days. Video recordings were taken and continuous sampling was used for four 30-minute sessions per day during public opening times. There were two study periods 26-months apart, only the first period showed significant results but this may have been due to the death of the original female lynx.

   Study and other actions tested

   Referenced paper

   Gilkison J.J., White B.C. & Taylor S. (1997) Feeding enrichment and behavioural changes in Canadian lynx Lynx canadensis at Louisville Zoo. International Zoo Yearbook, 35, 213-216.

4. A replicated, before-and-after study in 1997 of bush dogs Speothos venaticus in a zoo in the UK found that when food was hidden around the enclosure, searching behaviour increased compared to when food was thrown into the enclosure. Searching behaviour increased when food was hidden (6.1%) compared to baseline data (2.7%). Searching behaviour decreased as the treatment progressed. Eleven bush dogs in two enclosures were involved in the experiment. Their regular feeding regime consisted of meat chunks being thrown into the enclosure twice daily (chicken on bone, week old chicks, horse meat or unskinned rabbit). Instantaneous sampling with 15 second intervals was used for 30-minutes per day for each dog. During enrichment phase the entire daily food allowance was chopped into small chunks and hidden in the vegetation, rock crevices, under logs and within specially constructed wood-piles. Baseline data was collected for ten days, enrichment data for 20 days and post enrichment for ten days.

   Study and other actions tested

   Referenced paper

   Young R.J. (1997) Effect of wood-pile feeders on the behaviour of captive bush dogs (Speothos venaticus). Animal Welfare, 6, 145-152.

5. A small replicated, before-and-after study in 2007 of maned wolves Chrysocyon brachyurus in a research centre in the USA found that when dead mice were hidden around the enclosure, activity rates increased for three out of four wolves and exploratory behaviours increased for all wolves compared to when no mice were hidden. There was an increase in activity (proportion of active time per individual: 0.6, 0.8 and 0.7) and exploratory rates (events/minute for each individual: 0.9, 1.3, 1.7 and 2.3) when presented with hidden mice compared to no enrichment (proportion of active time per individual: 0.3, 0.2 and 0.5; exploratory: 0.13, 0.06, 0.07 and 0.05 events/minute). Four individually housed wolves were observed daily using focal sampling during 30-minute observation sessions for two weeks of no enrichment, two weeks of hiding mice, a further two weeks of no enrichment and two weeks of boomer balls.

   Study and other actions tested

   Referenced paper

   Cummings D., Brown J.L., Rodden M.D. & Songsasen N. (2007) Behavioral and physiologic responses to environmental enrichment in the maned wolf (Chrysocyon brachyurus). Zoo Biology, 26, 331-343.

6. A small replicated, before-and-after study in 2003 of Malayan sun bears Helarctos malayanus in a zoo in Germany found that hidden food once or twice per day with scent tracks leading to empty and filled food hiding places increased foraging behaviours and behavioural diversity compared to when food was not hidden. Foraging behaviours and behavioural diversity increased when feeds were hidden once daily (foraging: 40.15%/h; behavioural diversity: 2.3 Shannon Index) or twice daily (foraging: 43.73%/h; behavioural diversity: 2.9 Shannon Index) compared to when food was not hidden (foraging: 29%/h; behavioural diversity: 1.05 Shannon Index). For three out of four bears, walking behaviour increased (21.7%/h compared to when food was not hidden (6.8%/h). Four female sun bears were observed twice daily using continuous focal sampling to assess behavioural diversity and instantaneous scan sampling to assess activity budgets. Before treatments, baseline behavioural data were recorded for the standard feeding regime. The two treatments had the same conditions once or twice per day. This included hidden food in eight locations around the enclosure and up to 12 scent tracks of cinnamon dissolved in water.

   Study and other actions tested

   Referenced paper

   Schneider M., Nogge G. & Kolter L. (2014) Implementing unpredictability in feeding enrichment for Malayan sun bears (Helarctos malayanus). Zoo Biology, 33, 54-62.