Animal & Population Management

Scientific Papers

Two Giraffes
Carnivore longevity in zoos_Zoo Biology 2021.jpg

The historical development of juvenile mortality and adult longevity in zoo-kept carnivores (Roller et al., 2021).

July 2021

A study in Zoo Biology investigated the demographic data of 13 families and 95 species of zoo-housed carnivores:

 Data between 1950 and 2019;

 Neonate mortality decreased;

 Adult longevity increased;

 Results reflect continuous improvements of zoos through time.

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Breeding history and husbandry of the Superb Bird-of-paradise (Lophorina superba(Rimlinger, Theule & Bass, 2021).

June 2021

A paper in Zoo Biology described the breeding and husbandry of the superb bird-of-paradise in zoos:

Enclosure setup and pair management particularly important;

Male & female should be kept in adjacent enclosures with visual contact, given access for copulation & separated again afterwards;

Diet and enclosures described;

Despite challenges, this species can be successfully bred in zoos.

Offspring survival in breeding programme

Offspring survival changes over generations of captive breeding (Farquharson, Hogg & Grueber, 2021).

May 2021

A new paper in Nature Communications analysed pedigree data from 15 vertebrate species in captive breeding programmes:

Some species showed substantial increases or decreases in offspring survival over generations of captivity;

Differences between dam and sire effects;

Changes in fitness over generations, not explained by inbreeding, are occurring even in properly-managed programmes;

Important considerations for breeding & reintroduction programmes.

Pelican social networks and behaviour_Zo

Understanding sociality and behavior change associated with a nesting event in a captive flock of great white pelicans (Brereton, Fryer & Rose, 2021).

May 2021

New paper in Zoo Biology looked into sociality and behaviour in zoo-housed great white pelicans:

Increased vigilance levels in pre-nesting periods;

Non-random social associations observed;

Social structure: sub-adult birds associated more with each other;

Wider enclosure use with increased visitor presence;

Applications to captive pelican management and breeding.

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Burrowing in captive juvenile Desertas wolf spiders (Hogan ingens(Rowlands et al., 2021).

April 2021

New study in JZAR investigated burrowing behaviour in zoo-housed Desertas wolf spiders:
 Optimum substrate depth: >50 mm;
 Lighter, loosely packed substrates preferred;
 Stone size had positive effect on likelihood of burrow construction;
 Applications to captive husbandry and future reintroduction efforts.

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Photo credit: Bristol Zoo

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Assessing saddle‐billed stork (Ephippiorhynchus senegalensis) pair‐bonds and breeding behavior using behavior observed during multiple breeding seasons (Weibel et al., 2021).

April 2021

A study in Zoo Biology compared the behaviour and breeding success of two pairs of zoo-housed saddle-billed storks:
Higher reproductive success in one of the pairs: eggs produced & incubated in all breeding seasons;
"Successful" pair: higher rates of nesting behaviour and close proximity;
Pair compatibility may influence breeding success in this species.

Nocturnal activity katydid_Zoo Biology 2

Documenting nocturnal activity of dragon‐headed katydids (Lesina blanchardi) under artificial light (Baskir et al., 2021).

April 2021

A study in Zoo Biology investigated the nocturnal behaviour of dragon-headed katydids under artificial light:

Higher activity & enclosure use under red LEDs than under artificial daytime working lights;

Red LED illumination did not suppress nocturnal activity in this species.

Elephant Nocturnal activity_2021.jpg

Insights into Activity of Zoo Housed Asian Elephants (Elephas maximus) during Periods of Limited Staff and Visitor Presence, a Focus on Resting Behaviour (Finch et al., 2021).

March 2021

What are zoo elephants up to when no one is around? A paper in JZBG investigated the behaviour of the elephants at ZSL Whipsnade Zoo between 4 pm and 10 am:

Feeding (average 57.7%) and resting (average 28.2%) were the most frequent behaviours;

Resting was mostly done in close proximity to conspecifics;

Social associations can be formed during resting, and are facilitated by young individuals.

Giraffe Nocturnal Behaviour_Zoo Biology_

Biological and environmental factors as sources of variation in nocturnal behavior of giraffe (Burger et al., 2021).

March 2021

Paper in Zoo Biology investigated the nocturnal behaviour of zoo-housed giraffes:

Resting behaviours observed in approximately half of observations;

Age, subspecies & motherhood influenced nocturnal behaviour the most;

Husbandry & environmental factors did not have an effect on nocturnal behaviour;

These findings have potential applications to management of giraffes in captivity.

Ploughshare tortoise breeding_Zoo Biolog

Captive environmental change and induction of natural breeding and egg‐laying in ploughshare tortoises (Astrochelys yniphora(Kiryu et al., 2021).

February 2021

A study in Zoo Biology described how to induce natural breeding in captive ploughshare tortoises by replicating natural environmental conditions:

Temperature and humidity were seasonally adjusted to replicate the dry and rainy seasons of their natural habitat;

Natural breeding and egg laying observed one year after environment changes;

Important applications to captive breeding programmes of threatened tortoise species.

Hyena husbandry_JZAR_Miller et al 2021 (

When a habitat becomes a home: Housing and husbandry of spotted hyenas Crocuta crocuta at Disney’s Animal Kingdom® (Miller et al., 2021).

January 2021

A study in JZAR evaluated the impact of a training and enrichment programme on the behaviour of two spotted hyenas, when they moved from a research facility to Disney's Animal Kingdom:

Resting was the most common behaviour observed, followed by travelling.

Pacing decreased throughout the study;

Hyenas learned fast and responded positively to varied feeding strategies.

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Photo credit: Disney's Animal Kingdom.

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Urine collection conditioning in determining the oestrous cycle of a captive female giant panda Ailuropoda melanoleuca (Tay et al., 2021).

February 2021

New paper in JZAR described how urine collection conditioning can facilitate monitoring of the reproductive cycle of female giant pandas. The female panda at

Wildlife Reserves Singapore was trained to approach the animal keeper and urinate on cue in a specific location.

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The urine is then collected and used to monitor the oestrous cycle, helping to identify the best timing for artificial insemination (if necessary) and increasing the chances of breeding success.

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Photo credit: Wildlife Reserves Singapore

Golden mantella -Photo-credit-Luiza-Pass

Do captive golden mantella frogs recognise wild conspecifics calls? Responses to the playback of captive and wild calls (Passos et al., 2021).

January 2021

New study in JZAR investigated the responses of captive golden mantella frogs to playback calls from both wild and captive conspecifics:

Captive frogs showed a natural behavioural response to the vocalisations of wild males;

The calls from the captive males (especially the ones that had been in captivity for >5 generations) did not elicit a response;

Captivity had an effect on the calls of male frogs, which could affect their reproductive outcome if reintroduced into the wild.

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Photo credit: Luiza Passos

Zoo Biology_sand tiger reproduction.jpg

Natural environmental conditions and collaborative efforts provide the secret to success for sand tiger shark Carcharias taurus reproduction in aquaria (Wyffels et al., 2020).

August 2020

A study in Zoo Biology reported the birth of a sand tiger shark young (first time in the Americas), a species notably challenging to breed in captivity... The reasons behind this success were described:
Natural environmental conditions: natural seawater, light and seasonal temperature fluctuations;

Multi-institutional collaboration: individuals selected and brought together for breeding

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Effects of Lupron and surgical castration on fecal androgen metabolite concentrations and intermale aggression in capybaras (Hydrochoerus hydrochaeris(Yu et al., 2020).

December 2020

A study assessed the impacts of chemical sterilisation (i.e. Lupron®) & surgical castration on intraspecific aggression between three zoo-housed male capybaras:

Testosterone & sperm production decreased with chemical sterilisation;

Testosterone decreased in castrated males but in the one male left intact, it eventually returned to pre-Lupron levels;

Neither worked in reducing aggression between individuals, resulting in subsequent separation.

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Photo credit:  Smithsonian's National Zoo

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Comparison of reproductive success between parent-reared and hand-reared northern bald ibis Geronticus eremita in captivity during Proyecto Eremita (González et al., 2020)

September 2020

A study in JZAR compared reproductive success between parent-reared and hand-reared Northern bald ibises:
Similar reproductive success between parent- & hand-reared clutches;
Colony size had a negative effect on reproductive success;
Combination of hand- & parent-rearing improved reproductive output for reintroduction.

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Photo credit:  Zoobotánico Jerez

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Preference of intake of different tree leaves preserved with drying and ensiling by nyala antelope (Tragelaphus angasii) (Przybylo et al., 2020)

September 2020

Study investigated whether the browse preservation method (drying and ensiling) affects intake preferences in zoo-housed nyalas:

The nyalas showed preference for the leaves of some species (e.g. maple & oak) over others.

Generally, the method of preservation did not seem to affect their preferences.

The palatability of some browse species may be affected differently by method of preservation.

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Photo credit: Silesia Zoological Garden

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Zoo‐housed mammals do not avoid giving birth on weekends (Hosey et al., 2020)

September 2020

New study out in Zoo Biology investigated whether zoo-housed mammals avoid giving birth during the (generally busier) weekends:
 16 mammal species covered: including ungulates, primates & carnivores;
 No relationship found between birth rates & visitors numbers;
 No "weekend effect" found on birth rates.

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Photo credit: ZSL